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?

Let's assume the number of ₹5 and ₹10 coins in a bag are 'y' and 'z' respectively.

A bag contains ₹5 and ₹10 coins for a total of 40 coins and a total amount of ₹310.

y+z = 40    Eq.(i)

5y+10z = 310

y+2z = 62    Eq.(ii)

So Eq.(ii)-Eq.(i) ==> y+2z-(y+z) = 62-40

y+2z-y-z = 62-40

z = 22

Put the value of 'z' in Eq.(i).

y+22 = 40

y = 40-22

y = 18

Difference between the amount made up of all ₹10 coins and the amount made up of all ₹5 coins = 10z-5y

= $$10\times22-5\times18$$

= 220-90

= ₹130