Question

curtain hook cost 50 for 8. how many can I buy for rs 25?

Answer 1

Well first you need to know how much each hook costs alone
So if you can get 8 for 50 dollars, 50/8 = 6.25. 

Each hook costs 6.25 

Now to see how many you can guy with 6.25, you divide 25/6.25 = 4 

You can buy 4 hooks for 25 dollars :)

Answer 2

First you divide 50/8=6.25
25/6.25=4
So, 4 book cost 24