Study buddies anyone?

Water flows at a steady rate from a tap. its takes 40 seconds to fill a 4 litre watering can from the tap. the rate at which water flows from the tap is halved. complete: 4 litres into cm3

Witch represents the inverse of the function f(x)=1/4x-12

Asequence is defined recursively using the formula f(n + 1) =f(n) - 5. which sequence could be