Perry, maria, and lorna are painting rooms in a college dormitory. working alone, perry can paint a standard room in 3 hours, maria can paint a standard room in 2 hours, and lorna can paint a standard room in 2 hours 30 minutes. perry, maria, and lorna have decided that, to speed up the work, 2 of them will paint a standard room together. select the value closest to the shortest time in which a 2-person team could paint a standard room, and select the value closest to the longest time in which a 2-person team could paint a standard room, with each person working at his or her respective rate. make only two selections, one in each column.

We know that
1) perry can paint a standard room in 3 hours
so
100% of the room> 3 hours
x%> 1 hour
x=100/3< x=33.33%

2) maria can paint a standard room in 2 hours
so
100% of the room> 2 hours
x%> 1 hour
x=100/2< x=50%

3) lorna can paint a standard room in 2.5 hours
so
100% of the room> 2.5 hours
x%> 1 hour
x=100/2.5< x=40 %

therefore
perry can paint 33.33% of a standard room in 1 hour
maria can paint 50 % of a standard room in 1 hour
lorna can paint 40 % of a standard room in 1 hour

Part a) Find the value closest to the shortest time in which a 2-person team could paint a standard room
the value closest to the shortest time is which maria and lorna

team (maria +lorna) =(50%+40%)> 90%  in 1 hour
so
90%> 1 hour
100%> x
x+100/90> x=1.11 hours> 1 h 7 min

Part b) Find the value closest to the longest time in which a 2-person team could paint a standard room
the value closest to the longest time is which perry and lorna

team (perry+lorna) =(33.33%+40%)> 73.33%  in 1 hour
so
73.33%> 1 hour
100%> x
x+100/73.33> x=1.36 hours> 1 h 22 min

21/2 or 5/2