Tina can weed her vegetable garden completely in 80 minutes. Her friend Marisa can do the same task in 60 minutes. If they work​ together, how long does it

Question

what would be the common denominater  

 

Answer 1

1/80+1/60=1/x

common denominator is 240x, so multiply every term by 240x, you will get

3x+4x=240

7x=240

x=34.285 mins

Answer 2

t/80 + t/60 = 1

 

LCD? try 240.

 

Can you solve now and answer?