HELP I HAVE TO FINISH IN 2 HOURS shannon and sarah are mowing a field. shannon can finish mowing by herself in 2 hours. sarah can finish in 4 hours. how long will it take them to mow the field together?

1h 20m

Step-by-step explanation:

Let the total amount of work be x.

Shannon:

2h = x

1h = x

So basically Shannon does  x work per hour.

Sarah:

4h = x

1h = x

So basically Sarah does x work per hour.

Together:

1h = x + x

    = x + x

    = x

Amount of time spent = x ÷ x

                                     = x × x

                                     = h

                                     = 1h

                                     = 1h 20m

-2

7 - 9 = -2

reversed:

-2 + 9 = 7