Aptitude - Numbers - Discussion

Discussion Forum : Numbers - General Questions (Q.No. 21)
21.
Which of the following number is divisible by 24 ?
35718
63810
537804
3125736
Answer: Option
Explanation:

24 = 3 x8, where 3 and 8 co-prime.

Clearly, 35718 is not divisible by 8, as 718 is not divisible by 8.

Similarly, 63810 is not divisible by 8 and 537804 is not divisible by 8.

Consider option (D),

Sum of digits = (3 + 1 + 2 + 5 + 7 + 3 + 6) = 27, which is divisible by 3.

Also, 736 is divisible by 8.

3125736 is divisible by (3 x 8), i.e., 24.

Discussion:
56 comments Page 6 of 6.

Nikhil said:   5 years ago
The number should be divisible by both 3 and 8.
Here 24 is LCM so among those four options whichever has factors 24 is the answer.
And here only option (D) is satisfying this condition.
(4)

Srikanth said:   4 years ago
Thanks @Naresh.
(4)

ANIL MEGHWAL said:   4 years ago
35718 = 3+5+7+1+8 = 24.
63810 = 6+3+8+1+0 = 18.
537804 = 5+3+7+8+0+4 = 27.
3125736 = 3+1+2+5+7+3+6 = 27.

According to this, concept option 1 should be also correct.
(14)

Mayur said:   3 years ago
@Anil Meghwal.

718 is not completely divisible by 8 hence option A is ruled out. B

But, options C & D both are correct.
(2)

Devesh Kinkar said:   6 months ago
To check if a number is divisible by 24, we use the divisibility rules of 8 and 3 because:
24 = 8×3.

Step 1: Check divisibility by 3.
A number is divisible by 3 if the sum of its digits is divisible by 3.

Step 2: Check divisibility by 8.
A number is divisible by 8 if its last three digits form a number that is divisible by 8.
(1)

Aman kumarPatwa said:   1 month ago
Simply find the prime factor of 24.

Which is 8x3 => check 24 is divisible by both.

For 3 => check the sum of all /3 & for 8 checks only last 3 digit is/by 8 or not, if yes, plus also 3 answer is satisfied parallel, then the correct answer is to be determined.


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