Marshall bought 10 bags of chips for his school party. A bag of plain chips cost $2.00, and a bag of flavored chips cost $2.50. He spent a total of $23.00

Question

Marshall bought 10 bags of chips for his school party. A bag of plain chips cost $2.00, and a bag of flavored chips cost $2.50. He spent a total of $23.00 on chips. How many bags of flavored chips did he buy?

Answer 1

Hello, Anna,

We can set up several equations based on what is known. For the number of bags of each, I'll use PC for plain chips and FC for flavored chips.

We know that PC + FC = 10 bags

And the total cost is made up of the sum of the cost of each times it's number.

2PC + 2.5FC = total cost, which is $23.

Rewriting these:

PC+FC=10

2PC+2.5FC=23

rewrite the first:

PC=10-FC and then substitute this definition of PC into the second equation:

2(10-FC)+2.5FC=23

20 - 2FC + 2.5FC =23

0.5FC = 3

FC = 6

Since PC = 10 - FC, we can find PC = 6

Check these answers:

Do 4 bags of plain chips, at $2 each, plus 6 bags of flavored chips, at $2.5 each, add to $23?

2*4 + 2.5*6 = ?

8 + 15 = $23 Yum, yes.

I hope you "enjoy" this problem,

Bob

Answer 2

F=# flavored

P=# plain

F+P=10

2.5F + 2P = 23

Multiply the firs equation by 2 and subtract

.5F=3 => F=6

You finish it!