SOLUTION: Mrs Lee bought 50 books for $50. She paid $4 for each of the big books and$1 for 4 smaller books. How many big books and small books did she buy?

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Question 1090781: Mrs Lee bought 50 books for $50. She paid $4 for each of the big books and$1 for 4 smaller books. How many big books and small books did she buy?
Found 2 solutions by josgarithmetic, ikleyn:
Answer by josgarithmetic(39625) About Me  (Show Source):
You can put this solution on YOUR website!
x of the small books
y of the big books
system%28x%2By=50%2C%281%2F4%29x%2B4y=50%29
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x%2B16y=200, and x=50-y;
%2850-y%29%2B16y=200
50%2B15y=200
15y=150
highlight%28y=10%29
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highlight%28x=40%29
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40 of the small books and 10 of the big books.

Answer by ikleyn(52852) About Me  (Show Source):
You can put this solution on YOUR website!
.
A combination of (1 big book plus 4 small books) costs exactly 5 dollars and contains 5 books.


So, 10 times this combination satisfies/satisfy to the condition.


Answer. 10 big books and 4*10 = 40 small books.


I was lasy to write and to solve the problem using the system of equations.
So, I solved it MENTALLY, instead.