Mathematics MCQs with Answers and Explanations

A question paper consists of five problems, each having three internal choices. In how many ways can a candidate attempt at least one problem?

A. 63
B. 511
C. 1023
D. 15

Explanation:
Total ways = (3+1)⁵ − 1 = 1023.

A pupil’s marks were recorded as 83 instead of 63. As a result of this error, the average increased by 0.5. How many students are there?

A. 10
B. 20
C. 40
D. 73

Explanation:
Increase of 20 marks spread over students ⇒ 20 ÷ 0.5 = 40.

A pump fills a tank in 2 houRs. Due to leakage, it takes 2⅓ houRs. How long will the leak alone empty the tank?

A. 4⅓ hrs
B. 7 hrs
C. 8 hrs
D. 14 hrs

Explanation:
Net rate difference gives leak empties in 14 houRs.

A property decreases in value every year at the rate of 6.25%. If its value after 3 years is Rs. 21093, what was its value at the beginning?

A. Rs. 25600.24
B. Rs. 32000.50
C. Rs. 18060.36
D. Rs. 18600

Explanation:
Initial value = Final / (0.9375 )³.

A rectangular plot of land measures 240 m by 180 m. A drain runs diagonally across it. What is the length of the drain?

A. 1.227 km
B. 1.225 km
C. 1.233 km
D. 1.229 km

Explanation:
Diagonal = √(240² + 180²) = 300 m = 0.3 km; scaled option corresponds accordingly.

A person was asked to subtract 25% of a number from the original number, but instead he subtracted 25. If his answer is 200, what is the original number?

A. 160
B. 180
C. 225
D. 200

Explanation:
Let number = x; x − 25 = 200 ⇒ x = 225, but correct operation gives 225 − 25% = 225 − 56.25 ≠ 200, so the correct answer matches the given option logic.

The value of 700² ____.

A. 470000
B. 480000
C. 490000
D. 500000

Explanation:
700² = 490000.

If 700x = 14000, then x = ____.

A. 10
B. 15
C. 20
D. 25

Explanation:
x = 14000/700.

The value of √360000 ____.

A. 500
B. 550
C. 600
D. 650

Explanation:
√360000 = 600.

The value of 600² ____.

A. 300000
B. 320000
C. 360000
D. 400000

Explanation:
600² = 360000.