Question

check whether a-3,a-5,a-7 are in A.P​

Answer 1

Answer:

number is divisible by 4 when the last two numbers are divisible by 4.

Let’s look at an example. We want to know if 448 is divisible by 4, so we need to see if its last two numbers, 48, are divisible by 4.

48/4 = 12 and the remainder is 0.

Therefore, 448 is divisible by 4.

Criteria of divisibility by 9

A number is divisible by 9 when the sum of its digits is a multiple of 9.

For example, let’s check if 2610 is a multiple of 9.

2 + 6 + 1 + 0 = 9

Therefore 2610 is divisible by 9.