SOLUTION: 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 th

Algebra ->  Human-and-algebraic-language -> SOLUTION: 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 th      Log On


   

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?
Found 2 solutions by texttutoring, mananth:
Answer by texttutoring(324) About Me  (Show Source):
You can put this solution on YOUR website!
You have two variables, so you need to make two equations.

Let x = number of books bought online
Let y = number of books bought in store

There were 250 books sold in total:

x+y = 250

Their sales totaled $4995:

15x + 22.50y = 4995

Use elimination or substitution with the two equations to solve for x and y. I will use elimination, by multiplying the first equation by 15, then subtracting.

15x + 22.50y = 4995
15x + 15y = 3750
-----------------
0 + 7.50y = 1245

y = 1245/7.50
y= 166

Now find x:
x+y=250
x+166=250
x=250-166
x=84

So there were 84 books sold online, and 166 sold in the store. Hope this helps! Let me know if you need any more help.

Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
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?
...
books DISABLED_event_online= x numbers
books from store= y
x+y=250..........1
15x+22.50y = 4995...........2
...
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
...
m.ananth@hotmail.ca