# Andy's average driving speed for a 4-hour trip was 45 miles per hour. During the first 3 hours he drove 40 miles per hour. What was his average speed for the last hour of his trip?

Jul 25, 2018

color(indigo)("Average of speed of Andy in " 4^(th) " hour =60 " mph"

#### Explanation:

$\text{Dist. travelled by Andy in four hours " = 4 * 45 = 180 " miles}$

$\text{Dist. travelled in first 3 hrs " = 3 * 40 = 120 " mile}$

$\therefore \text{Dist. travelled in " 4^(th) " hour " = 180 - 120 = 60 " miles}$

color(indigo)("Average of speed of Andy in " 4^(th) " hour =60 " mph"