SOLUTION: A child in an airport is able to cover 342 meters in 3 minutes running at a steady speed down a moving sidewalk in the direction of the sidewalk's motion. Running at the same speed
Question 242291: A child in an airport is able to cover 342 meters in 3 minutes running at a steady speed down a moving sidewalk in the direction of the sidewalk's motion. Running at the same speed in the direction opposite to the sidewalk's movement, the child is able to cover 396 meters in 6 minutes. What is the child's running speed on a still sidewalk, and what is the speed of the moving sidewalk? Answer by ankor@dixie-net.com(22740) (Show Source):
You can put this solution on YOUR website! A child in an airport is able to cover 342 meters in 3 minutes running at a
steady speed down a moving sidewalk in the direction of the sidewalk's motion.
Running at the same speed in the direction opposite to the sidewalk's movement, the child is able to cover 396 meters in 6 minutes.
What is the child's running speed on a still sidewalk, and what is the speed of the moving sidewalk?
:
let c = child's running speed
let s = sidewalk speed
:
Effective speed
(c + s) = with the sidewalk movement
(c - s) = against the sidewalk
;
Write two distance equations: Dist = time * speed
:
3(c + s) = 342
6(c - s) = 396
;
Simplify both equations, divide the 1st by 3, and the 2nd by 6, results
c + s = 114
c - s = 66
-------------adding eliminates s, find c
2c + 0 = 180
c =
c = 90 meters/sec (the child)
:
Find s using equation c + s = 114
90 + s = 114
s = 114 - 90
s = 24 meters/sec (the sidewalk)
;
:
Check solution in the 2nd original equation
6(c - s) = 396
6(90-24) =
6(66) = 396
