Question

An office supply store sells wide-ruled notebook paper for $1.75 per pound. College-rule notebook paper costs $2.20 per pound. How many pounds of wide-ruled notebook paper are needed to make a 5-pound combination of paper that costs $2.11?

Answer 1

@Arfney

Answer 2

@uri

Answer 3

x = wide ruled paper = 1.75
y = college ruled paper = 2.20
wide rulled paper+ college rulled paper = 5

So we have the equations 1.75x + 2.20y = 2.11
and x + y = 5

Answer 4

So if we make everything a whole number by multiplying by 100
we get 175x +220y = 211
then using elimination (x + y = 5) *175
175x +220y = 211
175x + 175y = 875
subtracting them we get
45y = -6.64
dividing by 45 we get y = .14755
then plug that into the second equation
x + y = 5
x + .14755 = 5
x = 4.8524
I think I may have done something wrong...

Answer 5

Yeah.. I'm not really sure here.....

Answer 6

I think the answer is x = 19.755 and y = -14.755

Answer 7

I did it on paper and that is what I got.

Answer 8

okay, thanks!

Answer 9

Also to my answer that I posted
45y = -6.64 <-------- should be -664 not -6.64

So then dividing by 45 we get y = 14.755
then plug that into the second equation
x + y = 5
x - 14.755 = 5
x = 19.8524
So that is right!