10. Determine if 25110 is divisible by 45.
[Hint : 5 and 9 are co-prime numbers. Test the divisibility of the number by 5 and 9].
45 = 5 9
Factors of 5 = 1, 5
Factors of 9 = 1. 3, 9
Therefore, 5 and 9 are co-prime numbers.
Since the last digit of 25110 is 0. it is divisible by 5.
Sum of the digits of 25110 = 2 + 5 + 1 +1 + 0 = 9
As the sum of the digits of 25110 is divisible by 9, therefore. 25110 is divisible by 9.
Since the number is divisible by 5 and 9 both, it is divisible by 45.