Question 385312
A book cost $15 if bought online and $22.50 if bought at the store. The bookstore sold 250 books and took in $4995. How many books were bought online and how many were bought in the store?
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books online = x numbers
books from store= y
x+y=250..........1
15x+22.50y = 4995...........2
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multiply (1) by -15
-15x-15y=-3750
add this to (2)
15x-15x+22.50y-15y= -3750+4995
7.5y=1245
/7.5
y=1245/7.5 
y = 166 books from store.
Balance online. 84 books
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m.ananth@hotmail.ca