Question

A man ordered 3 times as many boxes of ballpoint pens as boxes of​ felt-tip pens. Ballpoint pens cost ​$4.32 per​ box, and​ felt-tip pens cost ​$3.45. If the​ man's order of pens totaled ​$82.05​, how many boxes of each type of pen did he​ buy?

Answer 1

He bought 5 boxes of felt-tip pens and 15 boxes of ball-point pens.

Explanation:

A man ordered 3 times as many boxes of ballpoint pens as boxes of felt-tip pens.

b = 3f ----------(1)

Ball point pens cost $4.32 per box, and felt-tip pens cost $3.45 per box, and and he ordered totaled $82.05

4.32b + 3.45f = $82.05 --------(2)

Now substitute for 'b' and solve for 'f'

4.32(3f) + 3.45f = 82.05

12.96f + 3.45f = 82.05

16.41f = 82.05

f = 5

number of boxes of felt-tip pens = 5

b = 3f

b = 3(5)

b = 15

number of boxes of ballpoint pens = 15