SOLUTION: I can weed the garden in 90 min. MY friend needs 20 min more. How long will it take us to do the job together

Algebra ->  Percentage-and-ratio-word-problems -> SOLUTION: I can weed the garden in 90 min. MY friend needs 20 min more. How long will it take us to do the job together      Log On


   

Question 621039: I can weed the garden in 90 min. MY friend needs 20 min more. How long will it take us to do the job together
Found 2 solutions by jim_thompson5910, matt501823:
Answer by jim_thompson5910(35256) About Me  (Show Source):
You can put this solution on YOUR website!
1/90 + 1/110 = 1/t

110t + 90t = 90*110

110t + 90t = 9900

200t = 9900

t = 9900/200

t = 49.5

So it will take 49.5 minutes (or 49 minutes 30 seconds) if you work together.

Answer by matt501823(7) About Me  (Show Source):
You can put this solution on YOUR website!
If you weed the garden in 90 minutes it means that you weed 6%2F9 of a garden per hour. If you friend takes 20 more minutes that means that he takes 110 minutes or that he weeds 6%2F11 of a garden per hour. If you find a common denominator between 6%2F9 and 6%2F11 you get 66%2F99 and 54%2F99. If you add 66 and 54 together you get 66%2B54=110. Thus you complete 110%2F99 of the weeding in 1 garden over the course of 1 hour. 110%2F99 can be simplified to 10%2F9 which amounts to the non-terminating decimal of 1.111. If you were to divide 1 hour (60 minutes) by 1.111 you would get 60%2F1.111=54 (in minutes). This means that it would take approximately 54 minutes for you and your friend to finish weeding 1 garden.