Question

4)Sarah averages 30 miles per hour driving from Orlando to Tampa. What must her average speed be on the return trip if the average speed for the whole round trip was 40 miles an hour

Answer 1

Answer:

y = 60 mph

Explanation:

given,

average speed of Sarah driving from Orlando to Tampa = 30 mph

average speed of return = ?

whole trip average speed = 40 mph

now,

$avg\ speed = \dfrac{total\ distance}{total\ time}$

Let x be the distance from Orlando to Tampa

y be the speed of return

$avg\ speed = \dfrac{x + x}{\dfrac{x}{30}+\dfrac{x}{y}}$

$avg\ speed = \dfrac{2}{\dfrac{1}{30}+\dfrac{1}{y}}$

$40= \dfrac{2\times 30 y}{30+y}$

 60  + 2 y = 3 y

    y = 60 mph

hence, speed of the return is equal to 60 mph.