I’ve tried 3 takes and just can’t seem to get it

Hello!

First you have to make the fraction have the same denominator so they are related

You can multiply the 1 and the 3 in 1/3 by 5 to get 5/15

You can multiply the 2 and the 5 in 2/5 by 3 to get 6/15

So he painted 5/15 of his room with 6/15 cans of paint.

Next you have to find out how much more of the room that needs to be painted

You can multiply 5/15 by 3 to get 1 which is his whole room

Now you do 6/15 * 3 to see how much paint he needs

This gives us the answer of 18/15 which is equal to  1 and 1/6 cans of paint

 Hope this helps!