15, 30, and 45 are.
The first three multiples of 235 are 235, 470 and 705. For them to be common, they need to be compared to another set of multiples. The first three common multiples of 2, 3 and 5 are 30, 60 and 90.
10, 20, 30 The common multiples of 5 and 10 are multiples of their lowest common multiple. The lcm of 5 and 10, is 10. Thus the first three common multiples are 10, 20, 30.
Since 3 is a factor of 15, the first three common multiples of 3 and 15 are 15, 30, and 45.
The anser to that Q is 30.
30 60 and 90
30 60 90
10, 20, 30.
90, 180, 270
10, 20, 30.
150, 300, 450
20 30 40