Carlos is saving up to buy two new books. he has saved 60% of the cost of one book costs $18 and 30% of the costs of another book that costs $21. how much more does he need to save?

the answer is 0.3175 hope that you ^w^

also you might actually want to put this picture up if you want people to solve it luckily i remember this question

x is the total time in minutes for the free response

you are given number of questions as 15 - m and time per item as 8 minutes

to find x multiply the two givens together:

x = 8 * (15-m) = 8(15-m)