Question

John drove for 3 hours at rate 50 km per hour and 2 hour for 60 kilometre per hour what was his average speed for the whole journey​

Answer 1

Given: Time taken by John, t₁ = 3hr and t₂ = 2hr

            speed, v₁ = 50km/hr and v₂ = 60 km/hr

To Find: Average speed of the whole journey, S.

Solution:

To calculate S, the formula used:

• Average speed = total distance covered(D) / total time taken(T)
• S = D / T

Here, T = t₁ + t₂

         T = 3 +2

            = 5hr

To calculate D, the formula used:

Distance = speed x time

d₁ = v₁ x t₁

    = 50 x 3

    = 150 km

d₂ = v₂ x t₂

    = 60 x 2

    = 120 km

So, D = d₁ + d₂

         = 150 + 120

         = 270 km

Applying the formula for S:

S = D/ T

S = 270 / 5

  = 54 km/hr

S = 54km/hr.

Hence the average speed of the whole journey is 54km/hr.

Answer 2

Explanation:

average speed: TOTAL DISTANCE

_______________

TOTAL TIME.

avg speed: 50 km + 60km.

____________

3hrs + 2hrs.

=110km.

______

5 hr's.

= 22kmp/h is the speed for the whole journey.

by sheikh hunain of class 6g

beacon house Gulshan campus.