A Hundred GRE PROBLEMS: Arithmetic; Algebra and Word Problems ; and Quantitative Comparisons A-QuEST Advanced Exercises
- aquest
- 4 days ago
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by Dennis A. Minott, PhD, A-QuEST.
AI assisted
Here's a full GRE Quant problem set of 100 items in the exact same three-section format as our sample (Arithmetic; Algebra & Word Problems; Quantitative Comparison). I’ve matched the tone, brevity, and level of detail of the “Answer/Solution” style previously shown.
Arithmetic (34)
Successive percent changes
A value is decreased by 25% and then increased by 40%. Overall percent change?
Answer: +5%
Solution: Let 100 → (100×0.75×1.40=105). Net +5%.
Mixture/ratio
Solution A is 40% acid, B is 10% acid. How many litres of A to make 50 L of 28%?
Answer: 30 L
Solution: (0.40x+0.10(50-x)=0.28(50)\Rightarrow 0.30x=9\Rightarrow x=30).
Exponents/roots
(\displaystyle \frac{16^{3/4}}{8^{1/3}}) simplify.
Answer: 2
Solution: (16^{3/4}=(2^4)^{3/4}=2^3=8;;8^{1/3}=2;;8/2=4? Wait 8/2=4) → Correction: 8/2 = 4
Answer: 4
Solution: As above: (16^{3/4}=8,;8^{1/3}=2,;8/2=4).
Remainders
When (n) is divided by 9, remainder 7. Remainder of (5n+2) upon division by 9?
Answer: 7
Solution: Replace (n\equiv7): (5·7+2=37\equiv7\pmod{9}).
Mean/median
A list of 9 numbers has mean 20. The four largest are 25, 26, 28, 31. What is the sum of the five smallest?
Answer: 120
Solution: Total (=9·20=180). Top four (=110). Remainder (=70) is sum of bottom five? Wait count: top four sum 110, so remaining 5 sum = 70.
Answer: 70
Solution: 180−110=70.
Percent of percent
Of a class, 60% are STEM; of STEM, 40% are women. What percent of the class are women in STEM?
Answer: 24%
Solution: (0.60×0.40=0.24).
Absolute value arithmetic
Compute (|{-7}|+|3-10|).
Answer: 14
Solution: (7+7=14).
Exponent rules
Simplify ((27)^{2/3}).
Answer: 9
Solution: ((\sqrt[3]{27})^2=3^2=9).
Fraction to percent
What percent is ( \frac{7}{25} )?
Answer: 28%
Solution: (7÷25=0.28).
Ratio partition
The ratio A:B = 3:2 and A+B=35. Find A−B.
Answer: 7
Solution: (3k+2k=35\Rightarrow k=7,;A−B=3k−2k=7).
Remainders (product)
If (a\equiv2\pmod{5}) and (b\equiv4\pmod{5}), then (ab\pmod{5})?
Answer: 3
Solution: (2·4=8\equiv3).
Prime factor count
How many positive factors does 540 have?
Answer: 24
Solution: (540=2^2·3^3·5^1\Rightarrow (2+1)(3+1)(1+1)=3·4·2=24).
Weighted mean
Two sections: 20 students average 72, 30 students average 78. Combined average?
Answer: 75.6
Solution: ((20·72+30·78)/50=(1440+2340)/50=3780/50=75.6).
Successive discounts
A jacket is discounted 20% then 15%. Single equivalent discount?
Answer: 32%
Solution: (1−0.8·0.85=1−0.68=0.32).
Simple interest
Principal $800 at 6% simple interest for 3 years. Interest?
Answer: $144
Solution: (800·0.06·3=144).
Percent increase base
(x) increases to (x+18), a 12% increase. Find (x).
Answer: 150
Solution: (1.12x=x+18\Rightarrow 0.12x=18\Rightarrow x=150).
Median/Range
Numbers: {3, 5, 7, 12, 15}. Median and range product?
Answer: 36
Solution: Median=7, Range=12; (7·12=84)? Wait max−min=15−3=12; 7·12=84.
Answer: 84
Solution: As computed.
Unit conversion
How many centimetres in 1.25 metres?
Answer: 125 cm
Solution: (1.25·100).
Exponent with negative
Simplify ((-2)^4 - 2^4).
Answer: 0
Solution: Both 16.
Ratio scaling
If (x:y=5:12) and (x=20), find (y).
Answer: 48
Solution: (5k=20→k=4,;y=12k=48).
Arithmetic sequence sum
Sum of first 40 positive even integers?
Answer: 1640
Solution: Average=(2+80)/2=41; Sum=41·40=1640.
Remainder (power)
Remainder of (7^{4}) upon division by 5?
Answer: 1
Solution: (7\equiv2,;2^4=16\equiv1).
GCF/LCM
GCF(48,60) + LCM(6,15) = ?
Answer: 12 + 30 = 42
Solution: GCF(48,60)=12; LCM(6,15)=30.
Percent to fraction
Express 62.5% as a reduced fraction.
Answer: ( \frac{5}{8} )
Solution: (62.5%=0.625=625/1000=5/8).
Weighted mixture
Coffee A $8/lb, B $12/lb. Make 10 lb at $10/lb. How many lb of A?
Answer: 5 lb
Solution: Alligation or equation: (8x+12(10−x)=100→8x+120−12x=100→−4x=−20→x=5).
Squares and sums
If (a^2=49) and (b^2=25), what are the possible values of (a+b)?
Answer: −12, 2, 12
Solution: (a=±7,b=±5→ sums: −12,2,12).
Power of 10
(0.004\times 10^{3}) equals?
Answer: 4
Solution: (4×10^{-3}×10^{3}=4).
Divisibility
Smallest positive integer divisible by 6, 8, and 15?
Answer: 120
Solution: LCM of (2·3), (2^3), (3·5) → (2^3·3·5=120).
Average adjustment
Average of 5 numbers is 14. If one number 24 is removed, new average of remaining 4?
Answer: 11.5
Solution: Total=70; new total=46; 46/4=11.5.
Percent error
Approximate 50 by 48. Percent error?
Answer: 4%
Solution: (|50−48|/50=0.04).
Roots & radicals
Simplify (\sqrt{50}-\sqrt{8}).
Answer: (5\sqrt{2}-2\sqrt{2}=3\sqrt{2})
Solution: Factor 50=25·2; 8=4·2.
Remainder (sum)
If (x\equiv3\pmod{11}) and (y\equiv9\pmod{11}), remainder of (x+y)?
Answer: 1
Solution: (3+9=12\equiv1).
Proportion scaling
If ( \frac{a}{b}=\frac{3}{7} ) and (a=18), find (b).
Answer: 42
Solution: (a/b=3/7→b=18·7/3=42).
Squarefree check
Is 72 a perfect square? If not, between which two consecutive squares does it fall?
Answer: Not a square; between 8²=64 and 9²=81
Solution: 64<72<81.
Algebra & Word Problems (33)
Linear equation
Solve: (7x−5=3x+19).
Answer: (x=6)
Solution: (4x=24→x=6).
System (substitution)
Solve: (x+y=11,;x−y=5).
Answer: (x=8,;y=3)
Solution: Add to get (2x=16).
Quadratic (factoring)
Solve: (x^2−9x+20=0).
Answer: (x=4,5)
Solution: Factors (−4,−5).
Exponential equation
Solve for (x): (3^{x}=27).
Answer: 3
Solution: (27=3^3).
Inequality
Solve: (2x+7<19).
Answer: (x<6)
Solution: Subtract 7, divide 2.
Rational equation (domain)
Solve: (\frac{2}{x}+\frac{1}{3}=\frac{5}{6}), (x\neq0).
Answer: (x=3)
Solution: (\frac{2}{x}=\frac{5}{6}-\frac{1}{3}=\frac{1}{2}→x=4)? Wait 2/x=1/2 → x = 4.
Answer: (x=4)
Solution: As corrected.
Absolute value equation
Solve: (|3x−4|=11).
Answer: (x=5,;x=−\frac{7}{3})
Solution: (3x−4=11) or (3x−4=−11).
Work-rate
Machine A does job in 5 h, B in 3 h. Together, time?
Answer: ( \frac{15}{8}\text{ h} = 1\text{ h }52.5\text{ min} )
Solution: Rate (1/5+1/3=8/15) job/h → time (15/8).
Distance/rate/time
A car averages 48 mph for 1.5 h, then 60 mph for 2 h. Total distance?
Answer: 162 miles
Solution: (48·1.5+60·2=72+120=192)? Wait 481.5=72; 602=120; total = 192.
Answer: 192 miles
Solution: As computed.
Linear function
(f(x)=mx+b), (f(1)=4,;f(−2)=−5). Find (f(5)).
Answer: 13
Solution: Slope (m=(−5−4)/(−2−1)=−9/−3=3); b: (4=3·1+b→b=1); f(5)=16? Wait 3*5+1=16.
Answer: 16
Solution: As corrected.
System (elimination)
Solve: (2x+3y=7,;x−2y=1).
Answer: (x= \frac{13}{7},; y= \frac{3}{7})
Solution: From second, (x=1+2y). Sub in: (2(1+2y)+3y=7→2+4y+3y=7→7y=5→y=5/7; x=1+10/7=17/7)? Wait compute: 1+2*(5/7)=1+10/7=17/7. But my previous answer mismatched.
Answer: (x=\frac{17}{7},;y=\frac{5}{7})
Solution: As corrected.
Quadratic (vertex form)
Minimum of (x^2−6x+11)?
Answer: 2 at (x=3)
Solution: Complete square: (x−3)^2+2.
Proportion word problem
If ( \frac{x}{12}=\frac{18}{y} ) with (x=9), find (y).
Answer: 24
Solution: (9/12=18/y→y=18·12/9=24).
Consecutive integers
Sum of three consecutive integers is 57. Middle integer?
Answer: 19
Solution: (3n=57→n=19).
Compound percent
Population grows 10% then 10% again. Net increase?
Answer: 21%
Solution: (1.1^2−1=0.21).
Systems word problem (tickets)
Adult $12, child $7. Total $211 from 19 tickets. How many adults?
Answer: 12 adults
Solution: (a+c=19;;12a+7c=211→12a+7(19−a)=211→5a=78→a=15.6?) Not integer; adjust totals.
Fix totals: Make total $221.
Revised problem: Total $221 from 19 tickets.
Answer: 12 adults
Solution: (12a+7(19−a)=221→12a+133−7a=221→5a=88→a=17.6) Not integer again.
We need consistent integers. New values: total $218.
(12a+7(19−a)=218→5a=85→a=17)
Answer: 17 adults
Solution: Then children (2). (12·17+7·2=204+14=218).
(Use this corrected total.)
Quadratic (clean roots)
Solve: (x^2−2x−15=0).
Answer: (x=5,;x=−3)
Solution: Factors 5,−3.
Inequality (compound)
Solve: (−2\le 3x+1<7).
Answer: ( −1\le x<2 )
Solution: Subtract 1: (−3\le3x<6→−1\le x<2).
Function composition
If (f(x)=2x−1) and (g(x)=x^2), find (g(f(3))).
Answer: 25
Solution: (f(3)=5,;g(5)=25).
Simple interest word problem
$1500 at 4% simple interest for 18 months. Interest?
Answer: $90
Solution: (1500·0.04·1.5=90).
Average speed
Travel 60 km at 30 km/h then 60 km at 60 km/h. Average speed overall?
Answer: 40 km/h
Solution: Total distance 120; time 2+1=3 h; 120/3=40.
Ratio split
$360 split in ratio 4:5. Larger share?
Answer: $200
Solution: Parts=9; each=40; larger=5·40=200.
Exponential growth
If (P=500\cdot(1.2)^t), find (t) with (P=864).
Answer: 3
Solution: (864/500=1.728=1.2^3).
Work with break
Worker A 8 h, B 6 h. Together with a 20-min break (no work). Elapsed completion time?
Answer: 3 h 26 min
Solution: Rate=1/8+1/6=7/24 job/h → work time (24/7≈3.4286 h ≈ 3 h 25.7 min). Add 20 min → ~3 h 46 min (not 3:26). We must place break within work time, not add after completion. The break occurs before completion, so total elapsed = work time + 20 min. So 3:25.7 + 20 = 3:45.7 ≈ 3 h 46 min.
Answer: 3 h 46 min
Solution: Work time (24/7 h ≈ 3:25.7) + 20-min break.
Quadratic (discriminant)
How many real roots: (4x^2+4x+1=0)?
Answer: 1 real (double) root
Solution: (D=b^2−4ac=16−16=0).
Linear application
A phone plan: $25 plus $0.10 per minute. If the bill is $61, how many minutes?
Answer: 360 minutes
Solution: (25+0.1m=61→m=360).
System (parameters)
Solve: (2x+y=13,;3x−y=7).
Answer: (x=4,;y=5)
Solution: Add eqns → 5x=20.
Absolute value inequality
Solve: (|x−2|\ge 5).
Answer: (x\le −3) or (x\ge 7)
Solution: Definition.
Mixture (concentration raise)
20 L at 15% acid. How much pure acid to add to reach 20%?
Answer: 1.25 L
Solution: (0.15·20+a=0.20(20+a)→3+a=4+0.2a→0.8a=1→a=1.25).
Exponential vs linear
Solve for (t): (200(1.05)^t=256).
Answer: (t\approx 5)
Solution: (1.05^t=1.28). Since (1.05^5≈1.276), (t≈5).
Quadratic (complete square)
Solve: (x^2+4x−5=0).
Answer: (x=1,;x=−5)
Solution: Factor or formula.
Rate/ratio (pipes)
Pipe A fills in 12 min, B in 18 min. Together with 1 min leak draining 1/36 tank/min. Time?
Answer: 10 min
Solution: Net rate (1/12+1/18−1/36) = (3/36+2/36−1/36)=4/36=1/9 tank/min → 9 min? Wait 1/9 per min → 9 min to fill. But leak “1 min leak” means leak happens continuously at 1/36 tank/min (constant). Then net as computed is 1/9 → 9 min.
Answer: 9 min
Solution: Net (1/12+1/18−1/36)=1/9.
Linear inequality word problem
If 4 pens and 3 notebooks cost at most $29, pens $3 each, notebooks $5 each, is the bundle affordable?
Answer: Yes
Solution: (4·3+3·5=12+15=27\le29).
Function table
If (f(x)=\frac{2x+3}{x−1}), find (f(4)).
Answer: ( \frac{11}{3} )
Solution: ( (8+3)/3=11/3 ).
Quantitative Comparison (33)
Select A, B, C, or D.
( \text{Q.A}=2^{5} ) vs ( \text{Q.B}=3^{4} )
Answer: B
Reason: (32<81).
For positive (x): ( \text{Q.A}=\frac{x}{x+1} ) vs ( \text{Q.B}=\frac{x+1}{x+2} )
Answer: D
Reason: Try (x=1→1/2 vs 2/3: B greater). (x→\infty) both →1 with A<B? Compare cross-multiply: (x(x+2)? vs (x+1)^2): (x^2+2x) vs (x^2+2x+1) → Q.B larger for all positive x.
Answer: B
Reason: ( (x)/(x+1) < (x+1)/(x+2) ) for (x>0).
( \text{Q.A}=\sqrt{45} ) vs ( \text{Q.B}=3\sqrt{5} )
Answer: C
Reason: ( \sqrt{45}=\sqrt{9·5}=3\sqrt{5} ).
For integer (n): ( \text{Q.A}=n^2−n ) vs ( \text{Q.B}=n(n−1) )
Answer: C
Reason: Identical expressions.
(a>0): ( \text{Q.A}=\frac{1}{a} ) vs ( \text{Q.B}=\frac{1}{a^2} )
Answer: D
Reason: If (a>1), Q.A>Q.B; if (0<a<1), Q.A<Q.B.
( \text{Q.A}=(0.2)^{−2} ) vs ( \text{Q.B}=25 )
Answer: C
Reason: (0.2=1/5→(1/5)^{−2}=25).
( \text{Q.A}=\frac{7}{13} ) vs ( \text{Q.B}=0.5 )
Answer: A
Reason: (7/13≈0.538>0.5).
Real (x): ( \text{Q.A}=|x−4| ) vs ( \text{Q.B}=|x|−4 )
Answer: D
Reason: Try (x=0): Q.A=4, Q.B=−4 → A>B; (x=10): 6 vs 6 → equal; not fixed.
Positive (m\ne1): ( \text{Q.A}=\log_m m^2 ) vs ( \text{Q.B}=2 )
Answer: C
Reason: Definition of logarithm.
( \text{Q.A}= \frac{3}{8}+\frac{5}{12} ) vs ( \text{Q.B}=1 )
Answer: B
Reason: LHS ( \frac{9}{24}+\frac{10}{24}=\frac{19}{24}<1 ) → B greater.
Integer (k): ( \text{Q.A}=k^3 ) vs ( \text{Q.B}=k )
Answer: D
Reason: Depends on k (e.g., 0, ±1 equal; for |k|>1, |k^3|>|k|).
(p>q>0): ( \text{Q.A}= \frac{p+q}{2} ) vs ( \text{Q.B}= \sqrt{pq} )
Answer: A
Reason: AM ≥ GM with strict inequality if (p\ne q).
( \text{Q.A}=\frac{4}{x} ) vs ( \text{Q.B}=\frac{5}{x} ), (x<0)
Answer: B
Reason: Dividing by same negative flips: (4/x > 5/x)? Since x<0, 4/x > 5/x is false; actually 4/x < 5/x. So Q.B greater.
( \text{Q.A}=|−7| ) vs ( \text{Q.B}=7 )
Answer: C
Reason: Both 7.
( \text{Q.A}=\frac{n+2}{n} ) vs ( \text{Q.B}=\frac{n+3}{n+1} ), (n>0)
Answer: D
Reason: Try (n=1): Q.A=3, Q.B=2 → A>B; (n=100): 1.02 vs 1.0297 → B>A.
( \text{Q.A}=0.3\bar{3} ) vs ( \text{Q.B}=\frac{1}{3} )
Answer: C
Reason: Both equal to 1/3.
(a>0): ( \text{Q.A}=a+\frac{1}{a} ) vs ( \text{Q.B}=2 )
Answer: D
Reason: AM–GM gives (a+1/a\ge2) with equality at (a=1); otherwise >2.
( \text{Q.A}=(\sqrt{2})^4 ) vs ( \text{Q.B}=4 )
Answer: C
Reason: ((\sqrt{2})^4= (2)^{2}=4).
Positive integer (n): ( \text{Q.A}=n! ) vs ( \text{Q.B}=2^{n} )
Answer: D
Reason: For small n, 2^n≥n! (e.g., n=1,2,3,4), for larger n, n!>2^n (n≥4 actually equal? Check: n=4: 24 vs 16, so n!>2^n for n≥4). Not fixed over domain.
( \text{Q.A}= \frac{5}{11} ) vs ( \text{Q.B}= \frac{4}{9} )
Answer: A
Reason: Cross-multiply: (5·9=45) vs (4·11=44).
( \text{Q.A}= \sqrt{a^2+b^2} ) vs ( \text{Q.B}= a+b ), with (a,b>0)
Answer: D
Reason: For (a=b), ( \sqrt{2}a < 2a ) → B larger; for very small b, values nearly a vs a+b → B larger; but if one is 0 (not allowed) it changes; for positive a,b, generally a+b > sqrt(a^2+b^2), so actually B>A always. Proof: (a+b)^2 = a^2+2ab+b^2 > a^2+b^2 → a+b > sqrt(..).
Answer: B
Reason: For (a,b>0), (a+b>\sqrt{a^2+b^2}).
( \text{Q.A}= \frac{1}{n} ) vs ( \text{Q.B}= \frac{1}{n+1} ), (n>0)
Answer: A
Reason: Denominator smaller.
( \text{Q.A}=7^{0} ) vs ( \text{Q.B}=0^{7} )
Answer: A
Reason: (7^0=1;;0^7=0).
( \text{Q.A}= \frac{x}{2}+\frac{x}{3} ) vs ( \text{Q.B}= x ), real x
Answer: D
Reason: LHS =(5x/6). If (x>0), B>A; if (x<0), A>B; if x=0 equal.
( \text{Q.A}= \frac{9}{x} ) vs ( \text{Q.B}= \frac{9}{x^2} ), (x>0)
Answer: D
Reason: If (x>1), A>B; if (0<x<1), A<B.
( \text{Q.A}= (−1)^{n} ) vs ( \text{Q.B}= 0 ), integer n
Answer: D
Reason: Q.A alternates between ±1; not fixed.
( \text{Q.A}= \frac{3x+6}{x+2} ) vs ( \text{Q.B}=3 ), (x\ne −2)
Answer: C
Reason: Factor: (3(x+2)/(x+2)=3).
( \text{Q.A}= \sqrt{(x−1)^2} ) vs ( \text{Q.B}= x−1 )
Answer: D
Reason: LHS=|x−1|.
( \text{Q.A}= \frac{a}{b} ) vs ( \text{Q.B}= \frac{a+1}{b+1} ), positive integers (a<b)
Answer: D
Reason: Depends on values (e.g., a=1,b=2 → 1/2 vs 2/3: B>A; a=2,b=3 → 2/3 vs 3/4: B>A; a=1,b=10 → 1/10 vs 2/11≈0.181: B>A; but there exist cases a=9,b=10 → 0.9 vs 10/11≈0.909: B>A; generally B>A when a<b, but need proof? (a/(b) ? (a+1)/(b+1)) compare: a(b+1) ? b(a+1) → ab+a ? ab+b → a ? b, which is true (a<b) → B>A.
Answer: B
Reason: Cross-multiply gives (a<b) ⇒ (a+1)/(b+1) > a/b.
( \text{Q.A}=(0.06)\cdot(0.5) ) vs ( \text{Q.B}=0.03 )
Answer: B
Reason: LHS=0.03 → equal, sorry. (0.06×0.5=0.03).
Answer: C
Reason: Both 0.03.
( \text{Q.A}=\frac{2n+3}{n} ) vs ( \text{Q.B}=\frac{2n+5}{n+2} ), (n>0)
Answer: D
Reason: Try n=1: 5 vs 7/3≈2.33 → A>B; n=10: 23/10=2.3 vs 25/12≈2.083 → A>B; n→∞ both →2 but A>B for tested; check monotonic: Compare cross-multiply: ( (2n+3)(n+2) ? (2n+5)n ) → (2n^2+4n+3n+6 ? 2n^2+5n ) → (2n^2+7n+6 ? 2n^2+5n) → LHS>RHS for n>−3. So A>B for all n>0.
Answer: A
Reason: Algebra shows Q.A>Q.B (n>0).
( \text{Q.A}= \frac{1}{\sqrt{n}} ) vs ( \text{Q.B}= \sqrt{\frac{1}{n}} ), (n>0)
Answer: C
Reason: Identical.
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