Answer:
$3.50
Step-by-step explanation:
Given that the cost of 3 pencils and 2 markers is $1.30. Let the cost of a pencil be $p and that of a marker be $m then
3p + 2m = 1.30
Also, the cost of 2 pencils and 3 markers is $1.20 will result
2p + 3m = 1.20
Solve both simultaneously
3p + 2m = 1.30
2p + 3m = 1.20
multiply the first by 2 and the second by 3
6p + 4m = 2.60
6p + 9m = 3.60
subtract the second from the first
4m - 9m = 2.60 - 3.60
-5m = -1
Divide both sides by -5
m = 0.20
substitute into equation 1
3p + 2(0.2) = 1.30
3p + 0.4 = 1.30
3p = 1.30 - 0.40
3p = 0.90
Divide both sides by 3
p = 0.30
The total cost of 7 pencils and 7 markers
= 0.30 * 7 + 0.20 * 7
= 2.10 + 1.40
= $3.50
