Question

Speed is inversely proportional to time. Koma travelled 3 1/2 hours at 120km per hour. On the return trip, Koma drove at 100 km per hour, how long will it take him to travel?

Answer 1

One way trip :

Travelling time, t1 = 3 1/2 hrs = 7/2 hrs

Speed, S1 = 120 km/h

We knoe Distance (D) = S1 × t1

D = 120 × 7/2

D = 60 × 7

D = 420 km

Round Trip :

Here distance, D will remain same = 420 km

Speed, S2 = 100 km/h

Time taken, t = ?

S2 = D / t

t = D / S2

t = 420 / 100

t = 4.2 hrs

Ans: It woould take him 4.2 hrs to travel on round trip.

Hope the solution is clear to you!! :)

Answer 2

Concept Introduction:

The speed of an item, which is a scalar number in everyday usage and kinematics, may be defined as the size of the change in direction per unit of time or the size of the change in position over time for an object.

Solution:

Given, Koma traveled $3.5$ hours at $120$ km per hour speed.

On the return trip, Koma drove at $100$ km per hour

We have to find the time he took to travel

The distance is = $( 3.5$ ×$120 ) = 420$ km

On the return trip, the required time is = $420/100= 4.2$ hr

Final Answer:

The final answer is $4.2$ hr

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