A plane is at an altitude of 25,195 feet above ground level. After 30 minutes, the plane rises by an altitude of 7,900 3/8 feet. Which of the following is true about the altitude of the plane after 30 minutes?

8 minutes

Step-by-step explanation:

To answer this, set the function y = 9.5x + 62.1 = to 138.1 and solve the resulting equation for x:

9.5x + 62.1 = 138.1

We must isolate x.  Start this process by subtracting 62.1 from both sides of this equation, obtaining:

9.5x = 76

Now divide both sides of this equation by 9.5:

x = 76/9.5 = 8

The water  reaches 138.1 degrees F after 8 minutes.