The graph of the cost of gas purchased depending on the number of gallons pumped has the points (4,15) and (8,30) what is the rate of change in the cost of gas as each gallon is pumped

To find the rate of change in the cost of gas as each gallon is pumped, we need to determine the slope of the line passing through the points (4,15) and (8,30).

The formula for calculating the slope of a line passing through two points (x₁, y₁) and (x₂, y₂) is given by:

slope = (y₂ - y₁) / (x₂ - x₁)

Using the given points (4,15) and (8,30), we have:

x₁ = 4, y₁ = 15
x₂ = 8, y₂ = 30

Plugging these values into the slope formula, we get:

slope = (30 - 15) / (8 - 4)
slope = 15 / 4
slope = 3.75

Therefore, the rate of change in the cost of gas as each gallon is pumped is 3.75.