SOLUTION: How long will it take Jones and Smith, together to plow a field which Jones can plow alone in 5 days and Smith alone in 8 days?

Question 227840: How long will it take Jones and Smith, together to plow a field which Jones can plow alone in 5 days and Smith alone in 8 days?
Answer by Earlsdon(6294) (Show Source): You can put this solution on YOUR website!
If Jones can plow the field in 5 days, then he can plow 1/5 of the field in 1 day.
If Smith can plow the field in 8 days, then he can plow 1/8 of the field in 1 day.
So together, they can plow (1/5 + 1/8 = 13/40) of the field in 1 day.
Which means that they can plow the entire field in 40/13 days.
40/13 = 3.077 days
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