Question

if a:b is equal to c:d equal to e:f equal to 1:2 then (3a+5c+7e) : : (3b+5d+7f)

Answer 1

3a/3b=5c/5d=7e/7f =1/2
3a+5c+7e/3b+5d+7f=1/2
so finally and is 1/2