How many integers between 1 and 200,inclusive, are divisible by both 3 and 4?

Question

Please help me with this question

Answer 1

Divisible by 4 if last two digits divisible by 4.

Divisible by 3 if sum of digits is divisible by 3.

 

First eliminate those not divisible by 4, e.g., 125

Then eliminate those not divisible by 3, e.g. 116

Answer 2

In order to both be divisible by 3 and 4, they have to be multiples of both 3 and 4.

 

The multiples of 3 are 3, 6, 9, 12,etc.

 

The multiples of 4 are 4, 8, 12, 16, etc

 

The numbers that are in both lists are the ones divisible by both 3 and 4 (12 for example)