erin and susan both took their dogs for a walk together they

erin and susan both took their dogs for a walk. together they walked 15 miles. if erin walked 3 miles less than susan, how far did susan walk with her dog?

Solution

e=s-3
e+s=15
s=3-s=15
2s=15+3
2s=18
s=18/2
s=9 miles was her walk.
e=9-3=6 miles was erin\'s walk
Proof:
6+9=15
15=15