word alegebra problem HELP

Question

he bought three times as many ball point pen  boxes at 4.33 each than filter pen boxes at 3.45 each and he spend 65.76 total how many boxes of each did he buy

Answer 1

Let b = the number of ball point pen boxes and f = the number of filter pen boxes.  Since he bought 3 times as many ball point pen boxes as filter boxes, we have:

 

b = 3f

 

The cost of the pens is:

 

Cost = Cost of ball point pens + Cost of filter pens

 

$65.76 = ($4.33)*b + ($3.45)*f

 

Since b = 3f, substitute 3f in place of b:

 

$65.76 = ($4.33)*3f + ($3.45)*(f)

 

65.76 = 12.99f + 3.45f

 

65.76 = 16.44f

 

Solve for f, the number of filter pens.  Once you have f, b = 3*f.