UPTET Feb 2014, q131
0. If the number 23583ab is completely divisible by 80, then the value of a - b is
- Option : A
- Explanation : 23583ab is divisible by 80, so it should be divisible by both 8 and 10 (factors of 80).
For 23583ab to be divisible by 10,
∴ b = 0
Now, by divisibility rule of 8,
3ab, i.e. 3a0 must be divisible by 8.
Only a = 2 makes it possible.
∴ a - b = 2.
