SOLUTION: Sam can mow the lawn in 20 minutes. Bob can mow the lawn in 30 minutes. if they work together, how long will it take to completely mow the lawn?

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Question 83319This question is from textbook introductory algebra
: Sam can mow the lawn in 20 minutes. Bob can mow the lawn in 30 minutes. if they work together, how long will it take to completely mow the lawn? This question is from textbook introductory algebra

Found 2 solutions by vertciel, ayshia:
Answer by vertciel(183) (Show Source):
You can put this solution on YOUR website!
The idea behind this problem is simple: one adds the rates of work.
However, you cannot add 20 and 30 minutes because they are not proportional, so we will make them proportionate.
If Sam mows the lawn in 20 minutes, he mows 1/20 of the lawn in 1 minute.
Likewise, Bob mows 1/30 of the lawn in 1 minute.
Now since the rates (ratios) of work are proportional to 1 minute, you can add them to find the time needed by both of them working together.

Answer by ayshia(2) (Show Source):
You can put this solution on YOUR website!
50 because 20+30= 50