Mia spent 1/4 of her money on a sandwich. He spent 2 times as much on a gift for his brother as on comic books. He had 3/8 of his money left. What fraction of his money did he spend on the books.

Answer:she spent 1/8 of her money on the books

Step-by-step explanation:

Let x represent the fraction of his money that he spent on the books.

Mia spent 1/4 of her money on a sandwich. He spent 2 times as much on a gift for his brother as on comic books. This means that the fraction of his money that she spent on a gift for her brother is 2x

Total amount that she spent is

1/4 + 2x + x = 1/4 + 3x = (1 + 12x) / 4

Amount that he has left would be

1 - (1 + 12x) / 4 = [4 - (1 + 12x) ]/4

He had 3/8 of his money left. It means that

[4 - (1 + 12x) ]/4 = 3/8

(4 - 1 - 12x) / 4 = 3/8

(3 - 12x) / 4 = 3/8

Cross multiplying, it becomes

8 (3 - 12x) = 12

24 - 96x = 12

96x = 24 - 12 = 12

x = 12/96 = 1/8