Aptitude - Numbers - Discussion

3+5+7+1+8 = 24 sum of digit is divisible by 24 then why this not an answer?

It is possible to divide the number by 2x4x3.

Simply you can do this in this way:

Let factor of 24=4*6.

So just check whether the last two digits are divided by 4 and 6 both then you'll get the answer easily.

5+4+7+8+0+4 is not divisible by 3.

Why we select only co prime numbers?

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

@Bindhu.

4 and 6 are not co-prime, because they share the common factor 2; and gcd(4,6)=2.

537804 is divisible by 2, 3, 4.

So 537804 is also divisible by 24 na?

If 537804 /24, the remainder will be 0. So the answer will be c and d.

---plz explain why c option cant be the answer

@Rajak

Because there are some short methods to find out weather the number is divided by 2,3,4,5,6,7,8,9,10,11.

For example:- if the last digit of any number is 0,2,4,6,8 then it is fully divided by 2 for example 63470.

If the sum of all the digits in number is divided by 3 then the number will be divide by the 3 for example = (3 + 1 + 2 + 5 + 7 + 3 + 6) = 27, which is divisible by 3 so the digit 3125736 will be fully divided by 3.

For 8 it is like if the last three digits are divided by eight then only it can be fully divided by 8 for example above... and so on.

How can you take only last 3 digits of a number ?