Photocopying. Quick Copy recently charged 49¢ per page for color copies and 7¢ per page for black-and-white copies. If Shirlee’s bill for 90 copies was $11.34, how many copies of each type were made?

Question

anonymous · Answer

49c+7b=11.34*100.
c+b=90
solve these two equation and get the value of c and b.
where c=no of color copies and b= no of black n white copies

cwrw238 · Answer

let number of black and white copies = x and pf color = y
49y + 7x = 1134
x + y = 90

anonymous · Answer

Ok I have that part figured out I am stuck after that

anonymous · Answer

Then use substitution by substituting 90-c for b.  

Your new equation would then be:

49c + 7(90 - c) = 11.34*100

cwrw238 · Answer

to solve  x secong equation by 7
7x + 7y = 630
now subtract this from ist equaton to eliminate x:
42y = 504
so y = 12
and x = 90 - 7 = 83
so there are 83 copies of black af collor

cwrw238 · Answer

83  of  black/white and 7 of color

anonymous · Answer

ok thanks

cwrw238 · Answer

soorry = typo there 83 of b/w and 12 of color ( not 7!)

anonymous · Answer

ok

cwrw238 · Answer

shhoot - i'm an idiot its 12 color and 90 - 12 = 78 b/w

check it out : - 12*49 + 78* 7 =  1134  - yess!!

correct answer 12 color 78 b/w

cwrw238 · Answer

sorry - the grand kids  are making a lot of noise tonight!!!

anonymous · Answer

that ok i understand

cwrw238 · Answer

lol - got there in the end!

anonymous · Answer

thanks again