Question

If you buy six pens and one mechanical pencil, it will cost $9. If you buy four pens and two mechanical pencils, it will cost $8. How much does each pen and mechanical pencil cost?
if you let p=the cost of pen
m= the cost of mechanical pencil

6p+1m=$9
4p+2m=$8
p=? m=?
please help what do i do to find these variables? thank u

Answer 1

Use Substitution or Elimination

1. pick one equation and solve for a variable

6p + 1m = 9

1m = 9-6p

m = 9 - 6p/ 1

m= 9-6p

2. substitute m into one of the equations given

4p + 2 ( 9-6p) = 10

4p + 18 - 12p = 10

4p - 12p = 10 - 18

-8p = -8 (divide both sides by -8)

p = 1

3. Insert p=1 into any of the equations

6p+1m = 9

6(1)+1m =9

6 + 1m = 9

1m = 9-6

1m= 3

m = 3