Rahim's collection contains US, Bangladeshi and British stamps. If the ratio of US to Bangladeshi stamps is 5 to 2 and the ratio of Bangladeshi to British stamps is 5 to 1, what is the ratio of US to British stamps?

Question: Rahim's collection contains US, Bangladeshi and British stamps. If the ratio of US to Bangladeshi stamps is 5 to 2 and the ratio of Bangladeshi to British stamps is 5 to 1, what is the ratio of US to British stamps?

Solution:
US : Bangladeshi = 5 : 2
= (5 × 5) : (2 × 5) ; [Multiply both parts by 5]
= 25 : 10

And,
Bangladeshi : British = 5 : 1
= (5 × 2) : (1 × 2) ; [Multiply both parts by 2]
= 10 : 2

∴ Combined Ratio of US : Bangladeshi : British = 25 : 10 : 2

So, US : British = 25 : 2