105, 210, 315
They are the first five multiples of their lowest common multiple: 140, 280, 420, 560, 700.
140, 280, 420, 560, 700
28 and 56
77, 154, 231 and so on.
140, 280, 420, 560, 700.
multiples of 56
7
21
Just 1.
It is 42
7.375
Three of them, yes.