Answer:
10 minutes.
Explanation:
Plane A = 1 ton of fuel left
Plane B = 21 tons of fuel Left
Fuel transfer = 1 ton per minute
In order for them to have the same amount of fuel,
We add up the fuel left in Plane A and Plane B
= 21 + 1 = 22 tons
This means each plane will equally have 11 tons
How long it will take to refuel plane A until both planes have the same amount of fuel is calculated as:
Plane B will transfer 10 tons of fuel to Plane A which would give plan A a total of 11 tons.
Since transfer rate = 1 ton per minute
= 1 ton = 1 minute
10 tons = 10 minutes.