The question is incomplete, the complete question is;
If in 0.5 min the tank gets 0.8 gallons of the water then
how many gallons will be in 1 min ?
how many gallons will be in 3 min?
and how long it takes for 40 gallons?
Answer:
1.6 gallons
4.8 gallons
25 mins
Explanation:
This question has to do with proportion.
If it takes 0.5 mins for the tank to get 0.8 gallons
in 1 minute the tank will get 0.8 * 1/0.5 = 1.6 gallons
In 3 minutes the tank will get 3 * 1.6 gallons = 4.8 gallons
if it takes 1 min to get 1.6 gallons
it will take x mins to get 40 gallons
x = 1 * 40/1.6 = 25 mins