Question

at a uniform speed of 54 kilometre per hour a car covers a certain distance in 50 minutes how much time will it take to cover the same distance at 30 kilometre per hour​

Answer 1

Answer:

A man travels at a speed of 54 km per hour. What distance will it cover in 3 hours and 20 minutes?

Atfirst we need to convert 3 hours 20 minutes into minutes i.e. 3×60+20 = 200 minutes

Now simply use the formula of time and distance…

Distance = speed × time

Speed = 54 km per hour i.e. 54 km in 60 minutes

Or in 1 minute 54/ 60 ( as we converted the unit in minutes )

Time = 200 minutes

Now Distance =

54/60 × 200

= 9× 20 ( cancelled out a single zero from 60 and 200 and dividing 54 by 6)

= 180 km

Ans: It will cover 180 km in 3 hours and 20 minutes.

Answer 2

First method (Unitary Method)

At 54 km per hour, time taken = 50 minutes

At 1 km per hour, time taken = (50×54) min

At 30 km per hour, time taken

.

Hence, the required time taken is 1 hr 30 min

Second Method (Method of Proportion)

Let the required time taken be x minutes.

Less Speed, More is the time taken

Speed( in km/hr) Time taken(in minutes)

54 50

30. x

.•. Ratio of speeds = Inverse ratio of time taken

=> 54:30 = x:50

=> 30×x = 54×50 = 54×50/30=90

Required time = 90 min = 1hr 30 min

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