Question

Find the value of k where 31K2 is divisible by 6

Answer 1

Given, 3 1 K 2 is divisible by 6. Then, it is also divisible by 2 and 3 both.

The divisibility rule for 2 is the last digit should be even number
so the last digit is 2..and it is even number...so it is divisible by 2

The divisibility rule for 3 is sum of all digits should be divisible by 3

So by trail and error method

When K = 0, 3+1+0+2=6 [divisible]
When K = 1, 3+1+1+2=7 [not divisible]
When K = 2, 3+1+2+2=8 [not divisible]
When K = 3, 3+1+3+2=9 [divisible]
When K = 4, 3+1+4+2=10[not divisible]
When K = 5, 3+1+5+2=11[not divisible]
When K = 6, 3+1+6+2=12 [divisible]
When K = 7, 3+1+7+2=13[not divisible]
When K = 8, 3+1+8+2=14[not divisible]
When K = 9, 3+1+9+2=15 [divisible]

So when K = 0, 3, 6, 9 , the number is divisible by 6.