Elena and Marcus jog after school each day. One day, Elena and Marcus jogged a total of 15 miles. Elena jogged 1 mile more than Marcus. Use a graph to find the number of miles each person jogged.

This is the concept of algebra, let the number of miles jogged by Marcus be x, the number of miles jogged by Elena is (x+1) miles:
Total number of miles jogged by the two individuals will be:
x+(x+1)=15
2x+1=15
putting like terms together we get:
2x=15-1
2x=14
hence
x=14/2 =7miles
therefore we conclude that Marcus jogged 7 miles while Elena jogged 8 miles.