Can someone please help me?

A

Step-by-step explanation:

it takes 45 hours to plant 100 trees, so his rate is 100/45 trees per hour.

and it takes rose 40 hrs to plant the 100 trees, so her rate is 100/40 trees per hour

So add those together to get (100/45+100/40)

and then multiply them by P(which is in hours) to equal 100

(100/45+100/40)p=100

then divide by 100 both sides to get

p/45+p/40=1

207/8 is the right