Question

Two sums of money are proportional to 8:9.n if the first is 20/- the other is

Answer 1

9/8 * 20 = 180/8 = 22.5

I do not understand why you inserted
.n" and "/-" into your question. The word "if" should be capitalized since it appears to start a sentence.

Answer 2

8/9=20/x

8x=20*9

8x=180 Divide with 8

x=180/8

x=(2*2*45)/(2*2*2)=45/2=22.5