20 is a possibility.
The only prime factor of 4 is 2. No prime number is a multiple of 5.
1, 2, 4
1, 2, 4
It must be 10.
Which number is a factor of 20 but not a multiple of 10?
1, 2, 5, 10
First factor 100: 100 = 2 * 2 * 5 * 5 From this, you can figure out that 100 is a multiple of 2, 5, and 4 (2*2).
1 and 5
60 and 120
10 is a factor of 20 (10 * 2 = 20) and is a multiple of five (5 * 2 = 10).
There is no such number. If a multiple of 4 is a factor of 30, then 4 must also be a factor of 30, but 4 is not a factor of 30 (the factors of 30 are: 1, 2, 3, 5, 6, 10, 15, 30), thus no such number exists.
No. 5 is a factor of 20, and 20 is a multiple of 5 .