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 3 of 6.

Ronit said:   8 years ago
Why we take only 8*3=24? why not other?

Keerthi said:   8 years ago
35718 can be divisible by 3 and 8 then why can't we divide with 24?

Prakarsh said:   8 years ago
We can not take 2*3*4 because 2&4 are not co primes, hence for 24 only possible co-primes are 8*3.

CO-PRIME: Those prime numbers which have only '1' as a common factor.

THANK YOU

Amit Thakuri said:   8 years ago
@Somgopal.

Will you make me understand how did we got 736 and from where?

Neha said:   8 years ago
@Thiru.

A set of numbers which do not have any other common factor other than 1 are called co-prime.

Neha said:   8 years ago
Thanks @Naresh.

Thiru said:   8 years ago
What is co-Prime?

Yogi said:   8 years ago
I don't understand the methods. Please anyone tell me the shortcut method for solving this.

Somgopal said:   8 years ago
Hi, friends.

A) 3+5+7+1+8=24 can divisible by 3
But 718 cannot divisible by 8.

B) 6+3+8+1+0=18 can divisible by 3
But 810 cannot divisible by 8.

Like that C also
Where as;

D)3+1+2+5+7+3+6=27 divisible by 3,
And 736 divisible by 8,
736/8 = 92.

Kumaresan said:   8 years ago
I don't understand these methods. Please anyone tell me the shortcut method for solving this.


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