1/x = 1/90 + 1/75
x = 40.9
Mr. Bailey mowed his yard in 90 minutes. His son Roy mows the yard in 75 minutes. How long will it take them if they work together (using 2 lawn mowers)?
4 answers
How to set up an equation for this problem? Thank you.
You have to ask yourself how much work gets done in 1 minute.
Mr Baily can do 1/90 of the total in a minute.
Add to that the amount that his son does in a minute.
The sum is how much of the job gets done by both together.
SO, if 1/3 gets done in a minute, the job takes 3 minutes. That's why the 1/x is used; it is the fraction that gets done each minute by all workers. You can have more terms.
If Paul comes over to help, and he can do the lawn in 80 minutes, then
1/x = 1/90 + 1/70 + 1/80
This is the way to set up all these work problems.
Mr Baily can do 1/90 of the total in a minute.
Add to that the amount that his son does in a minute.
The sum is how much of the job gets done by both together.
SO, if 1/3 gets done in a minute, the job takes 3 minutes. That's why the 1/x is used; it is the fraction that gets done each minute by all workers. You can have more terms.
If Paul comes over to help, and he can do the lawn in 80 minutes, then
1/x = 1/90 + 1/70 + 1/80
This is the way to set up all these work problems.
Thank