Help me solve the proportion please :(

If there are 12 moths and some have 31 days and others have 30 days how many have 28 days?

Kendra had twice as much money as kareem. kendra later spent $8 and kareem earned $6. by then, the two had the same amount of money. how much money did each have originally?

Apackage of five erasers cost 0. $.39 at this rate how many how much would 60 erasers cost in dollars and cents