SOLUTION: If a number is divisible by both 4 and 9, by what other numbers is it divisible?Explain. Thank you.

Algebra ->  Divisibility and Prime Numbers -> SOLUTION: If a number is divisible by both 4 and 9, by what other numbers is it divisible?Explain. Thank you.      Log On


   



Question 242631: If a number is divisible by both 4 and 9, by what other numbers is it divisible?Explain. Thank you.
Answer by Theo(13342) About Me  (Show Source):
You can put this solution on YOUR website!
since 9 is not a multiple of 4, the smallest number that can be divisible by 4 and 9 has to be a number that is the result of a product of 4 * 9.

if it is divisible by 4 and 9, then it has to be divisible by factors of 4 and 9.

that means it is divisible by 2 and 3 as well.

it should also be divisible by any combination of the factors of 4 and 9.

since the factors would be 2*2*3*3, then:

that would be:

2*2 = 4
2*3 = 6
3*3 = 9
2*2*3 = 12
2*3*3 = 18

4*9 * anything else would yield even more possibilities/.

example:

4*9*2 = 72

since there's another factor in the mix, 72 should be divisible by even more numbers that are combinations of factors of 2*2*3*3*2

those would be:

2*2 = 4
2*3 = 6
3*3 = 9
2*2*3 = 12
2*3*3 = 18
plus:
2*2*2 = 8
2*2*3*2 = 24
2*3*3*2 = 36