(From the erased outline, I'm assuming you're using models, and one unit is "U")

We start with:
Colin has 1U
Roy has 6U

After their friend gave them more stamps:
Colin has 1U+16
Roy has 6U+4

We know that Roy has 4 times as many stamps as Colin. So this means that if Colin wants to have the same number of stamps as Roy, we need to multiple whatever Colin has by 4.

So:
4 x (1U + 16) = 6U + 4

We can now solve for U:
4U + 64 = 6U + 4
2U = 60
1U = 30

As we wrote out above, the number of stamps that Roy has is 6U+4. And since we know that 1U = 30, hence:

(6 x 30) + 4 = 184

If you want to check, Colin has 46 stamps in the end, which is a quarter of what Roy has.