8/20 = (x5) 40/100
40/100 = 40%
answer = 40%
Ratio of US to Indian stamps is 5:2
U/I = 5:2
= 25:10
Ratio of Indian to British stamps is 5:1
I/B = 5:1
= 10:2
Now , Ratio of US to British stamps
U/B = 25:2
The answer is E.
The last answer - hypothenuse