The shop keeper sells three different types of marbles. The Blue marbles cost 20 paise each, the Green ones cost 90 paise each and the Black ones cost 5 paise each.
Each bag of marbles has 5 Black marbles, 1 Green marble and 2 Blue marbles. I bought a certain number of bags and paid Rs. 6.50 in all for the Blue and Green Marbles. How much did I pay for the Black marbles?
