Math by Grades Math by Topics Math Worksheets Math in Video Lessons Math for Specific Tests Math Fun and Games Exam Preparation Science Others
Algebra Motion Problems
Motion problems are based on the formula
d = rt
where d = distance, r = rate and t = time.
When solving motion problems, a sketch is often helpful and a table an be used for organizing information.
Example:
John and Philip who live 14 miles apart start at noon to walk toward each other at rates of 3 mph and 4 mph respectively. In how many hours will they meet?
Solution:
Let x = time walked.
r
t
d
John
3
x
3x
Philip
4
x
4x
3x + 4x = 14
7x = 14 x = 2
They will meet in 2 hours.
Example:
In still water, Peter’s boat goes 4 times as fast as the current in the river. He takes a 15-mile trip up the river and returns in 4 hours. Find the rate of the current.
Solution:
Let x = rate of the current.
r
t
d
down river
4x + x
15 / 5x
15
up river
4x - x
15 / 3x
15
The rate of the current is 2 mph.
Video
Motion Word Problems
Students should first draw a diagram to represent the relationship between the distances involved in the problem, then set up a chart based on the formula rate times time = distance. The chart is then used to set up the equation.
Custom Search
We welcome your feedback, comments and questions about this site - please submit your feedback via our Feedback page.