Answer :

a/b = 20

a + b = 84
b = 84 - a

a / (84 - a) = 20
a = 20 (84 - a)
a = 1680 - 20a
21a = 1680
a = 1680/21
a = 80

b = 84 - a
b = 84 - 80
b = 4

Therefore, the two numbers are 80 and 4