Evan's uncle gave him money for his birthday. evans plan is to put half his money un his savings account, spend 1 over 5 of his money on bubke gum, and buy cómic books with the money he has left. what portion of money will he spend con cómic books.

Put everything on a common denominator first so,

we have 1/2 and 1/5, the lowest common denominator is /10
when put over 10 we have 5/10 and 2/10

now add the two together

5/10 + 2/10 = 7/10, that is how much money has been claimed by the savings account and the bubble gum total. 

now subtract what has been claimed from the whole

10/10 - 7/10 = 3/10, this is the portion remaining to be spent on comic books

The answer is part a: use