SOLUTION: it takes Jacob 3 hours to dig a ditch, which is 6 feet deep. Johnson can accomplish the same task in 4 hours. how long will it take them to dig a ditch if they work together?

Question 557398: it takes Jacob 3 hours to dig a ditch, which is 6 feet deep. Johnson can accomplish the same task in 4 hours. how long will it take them to dig a ditch if they work together?
Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
it takes Jacob 3 hours to dig a ditch, which is 6 feet deep.
Johnson can accomplish the same task in 4 hours.
how long will it take them to dig a ditch if they work together?
:
Let t = time required when they work together
Let the completed job = 1 (a dug ditch 6' deep)
:
+ = 1
Multiply by 12. the least common denominator of 3 and 4:
12* + 12* = 12(1)
cancel the denominators and you have
4t + 3t = 12
7t = 12
t = 12/7
t = 1.714 hrs working together about 1 + .714(60) = 1 hr 43 minutes
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