Question 906224: Solve. A child is running on a moving sidewalk in an airport. When he runs against the sidewalk's motion, he travels 78ft in 13
seconds. When he runs with the sidewalk's motion, he travels 80ft in 10
seconds. What is the rate of the child on a still sidewalk and what is the rate of the moving sidewalk?
*PLEASE help. I tried this problem several times and I couldn't get the answer. Thanks :)
Answer by lwsshak3(11628)   (Show Source):
You can put this solution on YOUR website! Solve. A child is running on a moving sidewalk in an airport. When he runs against the sidewalk's motion, he travels 78ft in 13
seconds. When he runs with the sidewalk's motion, he travels 80ft in 10
seconds. What is the rate of the child on a still sidewalk and what is the rate of the moving sidewalk?
***
let x=rate of child on a still sidewalk
let c=rate of moving sidewalk
x-c=rate of child running against sidewalk motion
x+c=rate of child running with sidewalk motion
..
rate*travel time=distance
(x-c)*13=78
(x+c)*10=80
..
13x-13c=78
10x+10c=80
..
130x-130c=780 (Mult. by 10)
130x+130c=1040 (Mult. by 13)
add
260x=1820
x=7
10c=80-10x=80-70=10
x=1
rate of child on a still sidewalk=7 ft/sec
rate of moving sidewalk=1 ft/sec
|
|
|
