Carcass wrote:
If Michael can shovel all the snow off a standard driveway in 12 minutes, and Eamon can shovel all the snow off a standard driveway in 36 minutes, then working together, how many minutes would it take for them both to shovel all the snow off a standard driveway?
Let's
assign a "nice" value to the job of shoveling a driveway.
We want a value that works well with the given information: 12 minutes and 36 minutes.
So, let's say the job of shoveling a driveway consists of removing
36 cubic feet of snow.
Michael can shovel all the snow off a standard driveway in 12 minutesIn other words, Michael can shovel
36 cubic feet of snow in 12 minutes
So, Michael's RATE =
3 cubic feet per minute
Eamon can shovel all the snow off a standard driveway in 36 minutesIn other words, Eamon can shovel
36 cubic feet of snow in 36 minutes
So, Eamon's RATE =
1 cubic foot per minute
Working together, how many minutes would it take for them both to shovel all the snow off a standard driveway?Their
combined RATE =
3 +
1=
4 cubic feet per minute
Time = output/rate So, time to complete job =
36/
4 = 9 minutes
Answer: 9
Cheers,
Brent