Masha has two-ruble and five-ruble coins. If she takes all her two-ruble coins, she will be 60 rubles short to buy four pies. If all five-ruble coins - she will be 60 rubles short for five pies. And in total, she is 60 rubles short to buy six pies. How much does a pie cost?
If Masha takes all her two-ruble and five-ruble coins, she will be short of $60+60=120$ rubles for $4+5=9$ pies. On the other hand, she will be short of 60 rubles for 6 pies. That is, three pies cost 60 rubles.

## Answer

20 rubles.