Question

the ratio of 2 numbers is 7 to 5. if the sum of the numbers is 960 what are the numbers

Answer 1

a/b = 7/5
a+b = 960
a = 7b/5
7b/5 + b = 960
7b/5 + 5b/5 = 960
12b = 5*960
b = 5*960/12 = 400
a = 7*400/5 = 560

or:

7 + 5 = 12, 12 parts in 960, each part = 960/12=80
a is 7 parts of the whole, b is 5 parts, so 7*80 = 560 and 5*80 = 400