A camping store put in an order for flashlights and sleeping bags. The number of flashlights ordered was 3 times the number of sleeping bags. The flashlights cost $12.00 each, and the sleeping bags cost $45.00 each. If the total cost for the flashlights and the sleeping bags was $1215.00, how many flashlights and how many sleeping bags did they order?

Question

A camping store put in an order for flashlights and sleeping bags.  The number of flashlights ordered was 3 times the number of sleeping bags.  The flashlights cost $12.00 each, and the sleeping bags cost $45.00 each.  If the total cost for the flashlights and the sleeping bags was $1215.00, how many flashlights and how many sleeping bags did they order?

JJ · Answer

Let F = number of Flashlights
Let S = number of Sleeping Bags

F = 3S since the number of flashlights is three times the number of sleeping bags.

The value of the flashlighs is 12F
The value of the sleeping bags is 45S

The two equations are:

F = 3S
12F + 45S = 1215

Substitute the 3S for the F in the second equation.

12(3S) + 45 S = 1215.

solve for S, then find F in the original first equation.