Irene R. answered • 12/03/19

Engineer and Math Teacher in One!

Let's let x represent the number of calories in the pecan pie and y represent the number of calories in the lemon pie. Then since the sum of the calories for the two is 865 , we can write the following equation:

x + y = 865

Then since the number of calories in the pecan is 221 less than twice that of the lemon, we can write the following expression for the pecan :

2y - 221 = x

If we substitute 2y - 221 for x in our first equation, we can find the value of xy (or the calories in the lemon pie):

x + y = 865

2y - 221 + y = 865

Then combine liike terms and use inverse operations to solve for y:

3y - 221 = 865

3y -221 + 221 = 865 + 221

3y = 1086

3y/3 = 1086 /3

y= 362

So the number of calories in the ** lemon pie is 362**. Since the sum of the two numbers is 865, the

*pecan pie (or x) will be 503 calories.*To verify, 2y- 221 for pecan:

2 * 362 - 221 = 503