Rick has 20 pints of green paint. He uses 2 5 of it to paint a landscape and 3 10 of it while painting a clover. He decides that, for his next painting, he will need 12 3 4 pints of green paint. How much more paint will he need to buy?

He needs to buy 6 and 3/4 more pints.

Step-by-step explanation:

In order to find this, we first need to find out how much he has used. To do this, add together the two fractions of the whole that he has used.

2/5 + 3/10

4/10 + 3/10 = 7/10

Since he has used 7/10 of it already, we can multiply that by the original amount to find how much is gone.

7/10 * 20 = 14

So with 14 pints having been used, we know there is 6 pints left. To find how many more he needs to buy, subtract 6 from the amount he needs for the next painting.

12 and 3/4 - 6 = 6 and 3/4