Level 1
For every $15 Chloe saves, her father would give her $2.50. If she saved a total of $345 by herself after some months, how much would she have received from her father?
Level 2
Kenny had $63. He spent 17 of the money on a pen. He then spent 23 of his remaining money on a pencil case. How much did he spend on the pencil case?
Level 3
A coin bank contains some twenty-cent and fifty-cent coins in the ratio of 2 : 5.
When 10 fifty-cent coins are taken out and exchanged with some twenty-cent coins of the same value,
the ratio became 8 : 9.
Find the sum of money in the coin box in dollars.