human
Chris has a two-speed lawn mower. He can mow his entire lawn in "turtle" mode in 1 hour, or 40 minutes in "rabbit" mode. Today, he experimented by mowing half in turtle mode and half in rabbit mode. How many minutes did it take him to mow the lawn?
assistant
How long does it take Chris to mow half the lawn in turtle mode? ** He spends 60/2=<<60/2=30>>30 minutes in turtle mode
How long does it take Chris to mow half the lawn in rabbit mode? ** He spends 40/2=<<40/2=20>>20 minutes in rabbit mode
How many minutes did it take Chris to mow the lawn? ** He took 30+20=<<30+20=50>>50 minutes to mow the lawn.
#### 50