distance/rate/time linear equation

Question

A child is running on a moving sidewalk in an airport. When she runs against the sidewalk's motion, she travels 52ft

in 13

seconds. When she runs with the sidewalk's motion, she travels 66ft

in 11

seconds. What is the rate of the child on a still sidewalk and what is the rate of the moving sidewalk?      

Answer 1

s is the rate of the sidewalk

c is the child's rate

 

52 = (c - s)13

66 = (c + s)11

 

Can you solve the system and answer?