1 Millimeter is the answer I hope this helps you.
1/40+1/50=1/n
5/200+4/200=1/n
9/200=1/n
9n=200
n=200/9 minutes for both of them to prepare the field
☺☺☺☺
Answer: 4x4=16-7=9gallons
She will order 9 gallons
Step-by-step explanation:
For

, we have

and so

which is, again, only valid for

.