Question

Michael is going to the store 6 miles away. He rides his bike at 12 mph for the first half of the trip, then walks at 4 mph for the remainder. Michael's average speed for the trip to the store is closest to:

Answer 1

6 mph

Step-by-step explanation:

Total distance = 6 miles

Speed for the first half that means first 3 miles is 12 mph.

Speed for the next half that means next 3 miles is 4 mph.

Let t1 be the time taken to go for first half and then t2 be the time taken to go second half

By the use of formula for time.

time = distance / speed

`t_(1)=(3)/(12)=(1)/(4)h`

`t_(2)=(3)/(4)=(3)/(4)h`

total time taken in the 6 miles

`t = t_(1)+t_(2)=(1)/(4)+(3)/(4)=1 h`

Average speed is defined as the ratio of total distance traveled to the total time taken.

So, Average speed in the entire journey is given by

`V_(av)=(6)/(1)=6mph`