Which is a reasonable estimate of the constant of variation?

0.25 kWh per day

0.50 kWh per day

2.40 kWh per day

4.00 kWh per day

Answer: B 0.5 kWh per day

Step-by-step explanation:

Since the graph represents the function where electricity usage in kilowatts per hour of a clock radio varies directly with the number of days it is plugged into the wall current

The constant of variations will be the gradient (slope) of the graph.

Gradient = (Y2 - Y1) / (X2 - X1)

Where X1 = 2, X2 = 6, Y1 = 0.5, Y2 = 1.5

Substitute all the values into the formula

Gradient = (1.5 - 0.5) / (6 - 4)

Gradient = 1/2

Gradient = 0.5.

Therefore, a reasonable estimate of the constant of variation is 0.5 kWh per day