Question

Laura placed a bucket of water in her garden. Over the course of a week, she watched the water evaporate and recorded the volume of water left in the bucket each day.

Laura found the linear model that best fit the data was V=5.00−0.25n, where n is the number of days since she first placed the bucket and V is the volume of water, in liters, remaining in the bucket.

How many liters of water evaporated from the bucket every day?
How may liters where inside the bucket when Laura first placed it in the garden?

Answer 1

1. 0.5 L; 2. 5.00 L

Explanation:

V = 5.00 - 0.5n

If you include units, the equation becomes

V(in litres) = 5.00 L - (0.5 L/day) × (n days)

1. Rate of evaporation

When you include the units, it becomes easier to see that the water is evaporating at a rate of 0.5 L/day.

That is, 0.5 L of water evaporates each day.

The negative sign shows that the volume of water is decreasing.

2. Volume at the beginning

At the beginning of the experiment, n = 0. Then

V = 5.00 -0.5×0 = 5.00 - 0 = 5.00 L

The bucket originally contained 5.00 L of water.