Working together, Karen and Darren can mow their yard in 40 minutes if they each have a mower and mow at the same time. If Karen could mow the entire yard by herself in 60 minutes, how long would Darren take to mow the yard working by himself?

Step-by-step explanation:

Answer:

120mins

Step-by-step explanation:

Karen mows at 60mins, 1 peice of land

Let Darren mows that 1 peice of land at Xmins

The rate at which Karen mows the land would be 1/60 [takes 60mins for 1 piece]

The rate at which Darren mows the land would be 1/x

The average rate working together on one peice of land will be

the combined time

(1/60) + (1/X) = 1/40

[ (1/60) + (1/X) ]x40 = 1 yard

1/X = 1/40 - 1/60 = (3-2) / 120 = 1/120

1/X = 1/120

X=120mins

Darren's takes 120mins