The number of calories in a piece of pie is 20 less than 3 times the number of calories in a scoop of ice cream. The pie and ice cream together have 500 calories. How many calories are in each?

1 Answer
Jun 20, 2018

The piece of pie has 370 calories while the scoop of ice cream has 130 calories.

Explanation:

Let C_pCp represent the calories in the piece of pie,
and C_(ic)Cic represent the calories in the scoop of ice cream

From the problem: The calories of the pie is equal to 3 times the calories of the icecream, minus 20.
C_p = 3C_(ic) - 20Cp=3Cic20

Also from the problem, the calories of both added together is 500:
C_p + C_(ic) = 500Cp+Cic=500
C_p = 500 - C_(ic)Cp=500Cic

The first and last equation are equal (=C_pCp)
3C_(ic) - 20 = 500 - C_(ic)3Cic20=500Cic
4C_(ic) = 5204Cic=520

C_(ic) = 520/4 = 130Cic=5204=130

Then, we can use this value in any of the equations above to solve for C_pCp:
C_p = 3C_(ic) - 20Cp=3Cic20
C_p = 3*130 - 20Cp=313020
C_p = 370Cp=370

So, the piece of pie has 370 calories while the scoop of ice cream has 130 calories.