Joan can mow a 6 acre field in 2 hr. How long would it take her to mow a 3 acre field

We are given that Joan mows 6 acre in 2 hours, to know the time needed by her to mow 3 acres, we will simply do cross multiplication as follows:

6 acre ... take ... 2 hours

3 acre ... take ... ?

time needed = (3*2) / (6) = 6/6 = 1 hour

This mean that Joan will need 1 hour to mow 3 acre