### Home > INT1 > Chapter 4 > Lesson 4.1.1 > Problem4-7

4-7.

While on vacation with your family, you will be driving from Los Angeles to San Diego. If you take the freeway it is a distance of $144$ miles and the average freeway speed is $75$ miles per hour. If you take the scenic route along the coast, the drive will be $122$ miles at an average speed of 65 miles per hour. Which is the better route to take if you want to get to San Diego in the shortest amount of time? Show your work using Giant Ones.

Review the Math Notes box in Lesson 2.3.1 for help on dimensional analysis using Giant Ones.

$\text{Taking the freeway: }\frac{\text{144 miles}}{1}\cdot\frac{\text{1 hour}}{\text{75 miles}}=\frac{144}{75}\text{ hours} =1.92 \text{ hours}$

Now calculate the scenic route's driving time.