Mark and Jennie are bowling. Jennie’s score is double Mark’s score. If the sum of their score is 171

Mark and Jennie are bowling. Jennie’s score is double Mark’s score. If the sum of their score is 171, find each person’s score by writing out an equation.

Let Mark's score be m. Let Jennie's score be j. We're given two equations:

1. j = 2m
2. j + m = 171

Substitute equation (1) into equation (2):
2m + m = 171

Type this equation into our search engine to solve for m:
m = 57

To solve for j, we substitute m = 57 in equation (1) above:
j = 2(57)
j = 114