Question

Jan walks 2 miles at a constant rate of 3 miles per hour and then runs 1 mile at a constant rate of 8 miles per hour.

Answer 1

Answer:

(a).4.36 mph

(b) No

Step-by-step explanation:

We are given that

Jan covered distance,s1 =2 miles

Speed of Jan, a=3 mph

s2=1 mile

b=8mph

a.

We have to find the Jan' s average speed for the entire trip.

Average speed =$\frac{2ab}{a+b}$

Using the formula

Average speed=$\frac{2(3)(8)}{3+8}=4.36mph$

b.

Average speed with two speed

Average of Jan’s two speeds

$=\frac{a+b}{2}$

=$\frac{3+8}{2}=5.5 mph$

$4.36\neq 5.5$

Hence, the average speed in part (a) is not equal to the average of Jan’s two speeds.