Chapter 6: Q. 79 (page 698)

Fuel Efficiency The fuel efficiency (in miles per gallon) of a car going at a speed of x miles per hour is given by the polynomial $- \frac{1}{150} x^{2} + \frac{1}{3} x$ . Find the fuel efficiency when $x = 30$ mph.

Short Answer

Expert verified

The fuel efficiency at $x = 30$ mph is 4 miles per gallon.

Step by step solution

Step 1. Given information.

The fuel efficiency (in miles per gallon) of a car going at a speed of x miles per hour is:

$- \frac{1}{150} x^{2} + \frac{1}{3} x$

The speed of the car is $x = 30$ mph.

Step 2. Evaluate the expression for the given value.

Substitute $x = 30$ in the given expression.

$\begin{array}{rcl} - \frac{1}{150} (30)^{2} + \frac{1}{3} (30) & = & - \frac{1}{150} (900) + 10 \\ = & - 6 + 10 \\ = & 4 \end{array}$

Step 3. Conclusion.

The fuel efficiency at $x = 30$ mph is 4 miles per gallon.

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Fuel Efficiency The fuel efficiency (in miles per gallon) of a car going at a speed of x miles per hour is given by the polynomial $- \frac{1}{150} x^{2} + \frac{1}{3} x$ . Find the fuel efficiency when $x = 30$ mph.

Short Answer

Step by step solution

Step 1. Given information.

Step 2. Evaluate the expression for the given value.

Step 3. Conclusion.

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Fuel Efficiency The fuel efficiency (in miles per gallon) of a car going at a speed of x miles per hour is given by the polynomial -1150x2+13x. Find the fuel efficiency when x=30mph.

Short Answer

Step by step solution

Step 1. Given information.

Step 2. Evaluate the expression for the given value.

Step 3. Conclusion.

One App. One Place for Learning.

Most popular questions from this chapter

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Fuel Efficiency The fuel efficiency (in miles per gallon) of a car going at a speed of x miles per hour is given by the polynomial $- \frac{1}{150} x^{2} + \frac{1}{3} x$ . Find the fuel efficiency when $x = 30$ mph.