Ben and Arnoldo are sharing snacks. They have peanut treats and coconut treats. Ben ate 2 of the peanut treats and 4 of the coconut treats for a total of 160 calories. Arnoldo ate 3 of the peanut treats and 2 of the coconut treats for a total of 140 calories. They wrote the system below to represent the number of calories there are in the two types of treats.

So we have Ben ate 2 peanut treats (let p represent the calories in each peanut treat) and 4 coconut treats (let c represent the calories in each coconut treat). The sum of those calories is 160.

This is the equation for Ben:

2p+4c=160

I'm going to use the same representation here. p for the number of calories in each peanut treat and c for the number of calories in each coconut treat.

Arnold ate 3 p's and 2 c's for a sum of 140 calories:

Alrnoldo's equation is:

3p+2c=140

So we have the system:

2p+4c=160

3p+2c=140

I'm going to divide the first equation by 2 because each term is divisible by 2:

p+2c=80

3p+2c=140

This system is setup for elimination because the equations are in the same form and the second column have the same variable expression, 2c. So we are going to subtract to eliminate the variable c, that is 2c-2c=0.

p+2c=80

3p+2c=140

---------------------Subtract!

-2p+0=-60

-2p =-60

Divide both sides by -2:

p =30

So if p=30 and p+2c=80 , then 30+2c=80.

So let's solve:

30+2c=80 for c

Subtract 30 on both sides:

2c=50

Divide both sides by 2:

c=25

The number of calories in a peanut treat is 30.

The number of calories in a coconut treat is 25.