Selected MCQ

Current Question
The average of 7 numbers is 49. If one number is replaced by 70, the average becomes 50. What was the original number?
  • A. 40
  • B. 42
  • C. 43
  • D. 45
Correct Answer: B
Explanation:
Difference in total = 7 ⇒ original = 42.
Related Question 1
The average of 5 numbers is 20. If one number is excluded, the average becomes 18. What is excluded number ____.
  • A. 25
  • B. 28
  • C. 30
  • D. 35
Correct Answer: B
Explanation:
Total = 100, new total = 72 → difference = 28.
Related Question 2
The sum of five numbers is 655. The average of the first two is 85. Find the sum of the last three.
  • A. 180
  • B. 170
  • C. 190
  • D. 175
Correct Answer: A
Explanation:
Subtract known sum.
Related Question 3
If a number is increased by 50% and becomes 75, the original number is ____.
  • A. 40
  • B. 45
  • C. 50
  • D. 60
Correct Answer: C
Explanation:
x × 1.5 = 75 → x = 50.
Related Question 4
If a number is decreased by 25% and becomes 150, the original number is ____.
  • A. 200
  • B. 180
  • C. 220
  • D. 240
Correct Answer: A
Explanation:
x × 0.75 = 150 → x = 200.
Related Question 5
If a number is increased by 15% and becomes 230, the original number is ____.
  • A. 180
  • B. 200
  • C. 210
  • D. 220
Correct Answer: B
Explanation:
x × 1.15 = 230 → x = 200.