Question

For $7.52, you purchased 8 pens and highlighters from a local bookstore. Each highlighter costs $1.09 and each pen costs $.69. How many pens did you buy.

Answer 1

Let p be the number of pens purchased and h be the number of highlighters purchased.
p + h = 8 ..........(1)
h = 8 - p ...........(2)
0.69p + 1.09h = 7.52 ........(3)
Plugging the value for h from (2) into equation (3) we get:
0.69p + 1.09(8 - p) = 7.52 .....(4)
Expanding the bracket in (4) gives:
0.69p + 8.72 - 1.09p = 7.52
Therefore
-0.4p = -1.2
p = -1.2/-0.4 = 3
The answer is 3 pens.

Answer 2

p=number of pens
h=number of highlighters

p+h=8

1.09h+0.69p=752


p+h=8
minus h from both sides
p=8-h

sub that for p

1.09h+0.69(8-h)=7.52
1.09h+5.52-0.69h=7.52
0.4h+5.52=7.52
minus 5.52 from both sides
0.4h=2
divide both sides by 0.4
h=5

sub back

h=8-p
5=8-p
minus 8 frm both sides
-3=-p
mltiply both sides by -1
3=p



3 pens you bought