Which of the following numbers has both 2 and 5 as factors?
Factors of 8 are: 1, 2, 4 and 8
Factors of 15 are: 1, 3, 5 and 15
Factors of 30 are: 1, 2, 3, 5, 6, 10, 15 and 30
Factors of 12 are: 1, 2, 3, 4, 6 and 12
We can see that, only 30 has both 2 and 5 as factors
Hence the right answer is 30.