Selected MCQ

Current Question
One root of Equation x² − 12x + a = 0 is three times the other. Find a.
  • A. 29
  • B. 27
  • C. 28
  • D. 7
Correct Answer: B
Explanation:
Roots x, 3x → sum = 4x = 12 → x = 3 → a = 27.
Related Question 1
One pipe fills a tank three times as fast as another. Together they fill in 36 minutes. The time taken by the slower pipe is ____.
  • A. 81 min
  • B. 108 min
  • C. 144 min
  • D. 192 min
Correct Answer: C
Explanation:
Let slow rate = x → total = 4x → gives 144 min.
Related Question 2
Three years ago, the average age of 6 members was 19. Find the present age of a boy.
  • A. 1 year
  • B. 1.5 years
  • C. 2 years
  • D. 2.5 years
Correct Answer: A
Explanation:
Total age difference method.
Related Question 3
Three numbers are co-prime. The product of the first two is 551. Find the third.
  • A. 75
  • B. 81
  • C. 85
  • D. 89
Correct Answer: C
Explanation:
Factorization approach.
Related Question 4
Three men walk around a circular track of 11 km. Find a time for them to meet again.
  • A. 11 hours
  • B. 12 hours
  • C. 220 hours
  • D. 22 hours
Correct Answer: A
Explanation:
LCM of time intervals.
Related Question 5
Three dice are thrown. Find the number of outcomes where the sum is 10.
  • A. 36
  • B. 81
  • C. 91
  • D. 116
Correct Answer: C
Explanation:
Count valid combinations.