Question

The number 23a7b is divisible by 45. Find the value of (a + b), if .



select one:



a. 6



b. 4



c. 7



d. 9

Answer 1

A number is divisible by 45, if it's divisible by 9 and 5!

23a7b = divisible by 5, if b = 0 (or) 5

If b = 0 then 23a7b is divisible when

=>2 + 3 + a + 7 + b

=> 12 + a + 0

=> 12 + a is divisible by 9! It's divisible when a = 6!

If b = 5, then 23a7b is divisible by 9 when =>2 + 3 + a + 7 + b

=>12 + a + 5

=>17 + a is divisible by 9. It's divisible when a = 1

According to options, Answer is A) 6