Question

Your tire air pressure is decreasing at a constant rate so that the air pressure is a linear function of time. Initially there is 37 pounds per square inch of air pressure. Two hours later there is 27 pounds per square inch of air pressure. What is the slope of the linear function that is air pressure?

Answer 1

Slope = 5

Explanation:

the linear function can be represented by:

y = ax + b

where a is the slope.

initially there is 37 pounds per square inch of air pressure, so for x = 0, y = 37:

37 = 0a + b

b = 37

Then, after 2 hours, the pressure is 27 pounds per square inch of air pressure, so for x = 2 we have y = 27:

27 = 2a + 37

2a = 10

a = 5

So the slope is a = 5.