Selected MCQ

Current Question
The smallest number which when increased by 1 is divisible by 12, 18, 24 and 32 is ____.
  • A. 1439
  • B. 1440
  • C. 1459
  • D. 1449
Correct Answer: A
Explanation:
LCM − 1 = required number.
Related Question 1
Four prime numbers in ascending order have the smallest difference. Find the smallest.
  • A. 5
  • B. 7
  • C. 11
  • D. 13
Correct Answer: A
Explanation:
The closest primes start at 5.
Related Question 2
The smallest number which when divided by 20, 25, 35 and 40 leaves remainder 9 is ____.
  • A. 1994
  • B. 1494
  • C. 1349
  • D. 1496
Correct Answer: C
Explanation:
LCM + remainder answers.
Related Question 3
A number is selected at random from the first 50 natural numbeRs. What is the probability that it is divisible by 3 or 5?
  • A. 21/25
  • B. 17/25
  • C. 4/25
  • D. 8/25
Correct Answer: B
Explanation:
Count the multiples and apply the inclusion-exclusion principle → 34/50 = 17/25.
Related Question 4
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 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.