You and your friend are shopping for painting supplies. Your friend wants five bottles of paint and one set of paint brushes. You want seven bottles of paint and two sets of paint brushes. Each bottle of paint costs $3.69. If you and your friend's total cost is $51.69, what is the cost of one set of paint brushes?

So your friend bought 1 set of brush and 5 bottles of paint

you bought 2 brushes and 7 bottles of paint

1 bottle=3.69

friends cost+your cost=51.69

total you bought 3 brushes and 12 bottles

each bottle is 3.69

12*3.69=44.28

totalcost=51.69=3brushes+12bottles

51.69=3brushes+44.28

minus 44.28 from both sides

7.41=3brushes

divide both sides by 3

2.47=1brush

1 set of paint brushes=$2.47