Question

If `a/b = c/d` prove that each of the given ratios is equal to

`(5a + 4c)/(5b + 4d)`

Answer 1

Let `a/b = c/d = k`

Then a = bk and c = dk

`(5a + 4c)/(5b + 4d)` = `(5(bk) + 4(dk))/(5b + 4d) = (k(5b + 4d))/(5b + 4d) = k` = each given ratio