Question

A watering can dispenses water at a rate of 0.15 gallon per minute. The original volume of water in the can was 5 gallons. Which set of ordered pairs shows the volume of water in the can in gallons (y) as a function of time in minutes (x) from the first minute after the can starts dispensing water?

Answer 1

The changing rate of the amount of water in the watering can is a constant rate of 0.15 gallon per minute. 

The initial volume of water in the can at time = 0 is 5 gallons

The function will be a linear function in the form of $y=ax+b$ where 
$y$ is the volume of water in the can after $x$ minutes
$a$ is the changing rate
$b$ is the initial volume when time is 0

Substitute all the values into the form we have

$y=0.15x+5$