Which number among 38211, 38121, 32118, and 31128 is divisible by 24?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 31128.
A number is divisible by 24 if it is divisible by both 3 and 8.
Divisibility by 3: The sum of the digits must be divisible by 3.
Divisibility by 8: The last three digits must be divisible by 8.
38211:
Sum of digits = 3 + 8 + 2 + 1 + 1 = 15 (divisible by 3)
Last three digits = 211 (not divisible by 8)
Thus, 38211 is not divisible by 24.
38121:
Sum of digits = 3 + 8 + 1 + 2 + 1 = 15 (divisible by 3)
Last three digits = 121 (not divisible by 8)
Thus, 38121 is not divisible by 24.
32118:
Sum of digits = 3 + 2 + 1 + 1 + 8 = 15 (divisible by 3)
Last three digits = 118 (not divisible by 8)
Thus, 32118 is not divisible by 24.
31128:
Sum of digits = 3 + 1 + 1 + 2 + 8 = 15 (divisible by 3)
Last three digits = 128 (128 ÷ 8 = 16, so it is divisible by 8)
Therefore, 31128 is divisible by 24.