First, let's list the first 10 multiples of 6, 10, and 5.
6: 6, 12, 18, 24, 30, 36, 42, 48, 54, 60..
10: 10, 20, 30, 40, 50, 60, 70, 80, 90, 100..
5: 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60...
Ah ha!
Can you see a common multiple? It is 30, isn't it?
So 30 is our answer.
