Jo's collection contains US, Indian and British stamps. If the ratio of US to Indian stamps is 5:2 and the ratio of Indian to British stamps is 5:1, what is the ratio of US to British stamps?
A man buys postage stamps of 25 paise and 50 paise denominations for Rs.10. He buys 25 stamps in all. Find the number of 25 paise stamps he purchased.