Quantitative Aptitude

Correct answer: B

I is incorrect: the mode of 2, 4, 4, 5, 7, 7, 7, 9 → 7. Seven occurs three times, more than any other value. II is correct: the new average when 50 is added to four numbers with average 30 → 34. The total becomes 120+50=170 across five numbers.

Correct answer: C

4:6=10:x gives x=6×10/4.

Correct answer: A

I is correct: the larger share when Rs 840 is divided in the ratio 3:4 → 480. There are seven parts; the larger share is 840×4/7. II is correct: the ratio a:c as its first term when a:b=2:3 and b:c=9:10, with c represented by 10 → 6. Scale the first ratio to 6:9; then a:b:c=6:9:10.

Correct answer: C

I is incorrect: the mode of 2, 4, 4, 5, 7, 7, 7, 9 → 7. Seven occurs three times, more than any other value. II is correct: the litres of water added to 20 litres of pure milk to make milk 80% of the mixture → 5. The final volume is 20/0.8=25 litres, requiring 5 litres of water.

Correct answer: D

The required total is 88; the known values sum to 60.

Correct answer: B

I is incorrect: the fourth proportional to 4, 6 and 10 → 15. 4:6=10:x gives x=6×10/4. II is correct: the average of five numbers totalling 185 → 37. Average equals 185/5.

Correct answer: C

Seven occurs three times, more than any other value.

Correct answer: B

I is incorrect: the geometric mean of positive numbers 9 and 16 → 12. The positive square root of 9×16 is 12. II is correct: the larger share when Rs 840 is divided in the ratio 3:4 → 480. There are seven parts; the larger share is 840×4/7.

Correct answer: A

The final volume is 20/0.8=25 litres, requiring 5 litres of water.

Correct answer: C

I is incorrect: the ratio a:c as its first term when a:b=2:3 and b:c=9:10, with c represented by 10 → 6. Scale the first ratio to 6:9; then a:b:c=6:9:10. II is correct: the combined mean of 10 students averaging 40 and 15 averaging 50 → 46. The combined total is 400+750=1150 across 25 students.

Correct answer: B

Average equals 185/5.

Correct answer: A

I is correct: the value of x in the proportion 5:8=x:40 → 25. x=40×5/8. II is correct: the range of 13, 4, 21, 9, 17 → 17. Range equals maximum minus minimum: 21−4.

Correct answer: D

The positive square root of 9×16 is 12.

Correct answer: C

I is incorrect: the litres of water added to 20 litres of pure milk to make milk 80% of the mixture → 5. The final volume is 20/0.8=25 litres, requiring 5 litres of water. II is correct: the fourth proportional to 4, 6 and 10 → 15. 4:6=10:x gives x=6×10/4.

Correct answer: A

Scale the first ratio to 6:9; then a:b:c=6:9:10.

Correct answer: C

I is correct: the geometric mean of positive numbers 9 and 16 → 12. The positive square root of 9×16 is 12. II is correct: the average of five numbers totalling 185 → 37. Average equals 185/5.

Correct answer: B

The two central values are 9 and 12; their mean is 10.5.

Correct answer: A

I is incorrect: the larger share when Rs 840 is divided in the ratio 3:4 → 480. There are seven parts; the larger share is 840×4/7. II is correct: the litres of water added to 20 litres of pure milk to make milk 80% of the mixture → 5. The final volume is 20/0.8=25 litres, requiring 5 litres of water.

Correct answer: D

I is correct: the weighted mean of scores 60 and 80 with weights 3 and 2 → 68. The weighted mean is (60×3+80×2)/5. II is correct: the litres of water added to 20 litres of pure milk to make milk 80% of the mixture → 5. The final volume is 20/0.8=25 litres, requiring 5 litres of water.

Correct answer: B

Range equals maximum minus minimum: 21−4.

Correct answer: A

I is incorrect: the new average when 50 is added to four numbers with average 30 → 34. The total becomes 120+50=170 across five numbers. II is correct: the ratio a:c as its first term when a:b=2:3 and b:c=9:10, with c represented by 10 → 6. Scale the first ratio to 6:9; then a:b:c=6:9:10.

Correct answer: A

I is correct: the median of 3, 7, 9, 12, 15, 20 → 10.5. The two central values are 9 and 12; their mean is 10.5. II is correct: the milk volume in litres in 30 litres of milk-water mixture at ratio 3:2 → 18. Milk forms 3/5 of 30 litres.

Correct answer: B

The combined total is 400+750=1150 across 25 students.

Correct answer: C

I is correct: the value of x in the proportion 5:8=x:40 → 25. x=40×5/8. II is correct: the litres of water added to 20 litres of pure milk to make milk 80% of the mixture → 5. The final volume is 20/0.8=25 litres, requiring 5 litres of water.

Correct answer: A

The total becomes 120+50=170 across five numbers.