Question

A watering can dispenses water at the rate of 0.20 gallon per minute. The original volume of water in the can was 8 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 can starts dispensing water?

Answer 1

8-x(y)
or in words 8 minus x times y do the 8 minus x first then the times y

Answer 2

`S =\{ \forall x \geq 1,\, x,y \in \mathbb{R} | (x, 8 - 0.20\cdot x) \}`

Explanation:

The volume of water at a given time is modelled after the following expression:

`y = y_(o) - m\cdot x`

Where:

`y_(o)` - Original volume of water, in gallons.

`m` - Water discharge rate, in gallons per minute.

Expression needed to model the system is:

`y = 8\,gal -\left(0.20\,(gal)/(min) \right)\cdot x`

The ordered pairs from the first minute after the can starts dispensing water are:

`S =\{ \forall x \geq 1,\, x,y \in \mathbb{R} | (x, 8 - 0.20\cdot x) \}`