A bag contains ₹5 and ₹10 coins for a total of 40 coins and a total amount of ₹310. What is the difference between the amount made up of all ₹10 coins and the amount made up of all ₹5 coins?

₹130

Let no. of  ₹5 coins = x

No. of  ₹10 coins = 40 - x 

Total amount =  ₹310 

5x + 10(40 - x) = 310 

5x + 400 - 10x  = 310

                5x    =  90    ⇒ x = 18

Amount in the form of ₹5 coins = 5x = 5 x 18 =  ₹90

                                 ₹10 coins = 10(40 - x) = 10 x 22 =  ₹220 

Difference in these amounts -=  ₹220 -  ₹90 =  ₹130