A school librarian bought 30 books for a total of $130. A storybook cost $4, while a science book and math book cost $6 and $5 respectively. How many books in each category did she buy?

Question

[find 2 possible answers]

Answer 1

If there are x,y,z stories, science, and math, then
x+y+z = 30
4x+6y+5z = 130
There are many possible solutions. If you pick a value for x, then
y = x-20
z = 50-2x
So, clearly, 20<x<25
so, pick x=21, and that gives you y=1, z=8, for
21 stories, 1 science, 8 math

Answer 2

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