Question

From which number of the following numbers 7538876849 is divisible?

• A. 2
• B. 9
• C. 3
• D. 7

Answer 1

The correct option is D 7

Divisibility by 2
The number 7538876849 does not have an even number or 0 at ones place, so it is not divisible by 2.

Divisibility by 3
Sum of digits = 7 + 5 + 3 + 8 + 8 + 7 + 6 + 8 + 4 + 9 = 65
which is not divisible by 3, so the number 7538876849 is not divisible by 3.

Divisibility by 9
Sum of digits of 7538876849 is not divisible by 9 also. So, the number 7538876849 is not divisible by 9.

Divisibility by 7
Step 1: Make the number into groups of 3-digits each from right to left. If the left most group is less than 3 digits take it as group.
7 | 538 | 876 | 849 |
A B C D

Step 2: Add the groups in alternate places i.e. A + C and B + D.
A = 7, B = 538, C = 876, D = 849
So,
A + C = 7 + 876 = 883
B + D = 538 + 849 = 1387

Step 3 : Subtract 883 from 1387 and check the divisibility rule of 7 for the resultant 3 digit number.
1387 − 883 = 504

Since 504 is divisible by 7, hence 7538876849 is divisible by 7.