Question

You drive 4 km at 30 km/h and then another 4 km at 50 km/h. What is your average speed for the whole 8-km trip?

a. Less than 40 km/h.
b. Not enough information.
c. Equal to 40 km/h.
d. More than 40 km/h.

Answer 1

option A

Step-by-step explanation:

given,

drive 4 km at 30 km/h and

another 4 km at 50 km/h

average speed for the whole 8 Km trip = ?

time for the trip of first 4 km

distance = speed x time

`t_1 = (d)/(s)`

`t_1 = (4)/(30)`

t₁= 0.1333 hr

time from another 4 km trip

`t_2 = (d)/(s)`

`t_2= (4)/(50)`

t₂ = 0.08 hr

average speed

`s= (d)/(t)`

`s= (8)/(0.1333 + 0.08)`

`s= (8)/(0.2133)`

s = 37.50 Km/hr

Less than 40 Km/h

the correct answer is option A