Today I am sharing techniques and concepts for Time ,speed and Distance chapter. I hope it will be beneficial to all the readers.

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### Conversion of km/hr into meter/sec

Following formula is used in this case

The formula is:

Some tricky questions are given below:

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**1. Question**

A Van travels 800 km in 12 hours and another 400 km in 18 hours. Find the average speed of the car.

**Solution**

Formula of Average speed will be apply here i.e.

Average Speed = Total Distance/Total Time

Average Speed = (800 + 400) / (12 + 18)

Average Speed = 1200/30 =

**40**####
**2. Question**

A horse covers a distance of 750m in 2 min 30 sec. What is the speed in km/hr of the cyclist?

**Solution**

Speed = 750/150 = 5m/sec

(2 min 30 seconds = 150 seconds)

Now we have to find the speed in km/hr.

5m/sec = 5 × (18/5)km/hr =

**18km/hr**####
**3. Question**

Find the time taken to cover a distance of 360 km by a train moving at 20 meters/second.

**Solution**

Time = Distance / Speed

We need to convert the distance into meter per second

so, 360 × 5/18 = 100

Now by applying the formula of Time, we get

Time = 100 / 20 =

**5 hours**####
**4. Question**

How many minutes does Bajira take to cover a distance of 400 m, if he runs at a speed of 20km/hr?

**Solution**

Bajira's speed = 20 km/hr = (20 × 5/18) m/sec = 50/9 (m/sec)

Time taken to cover 400 m = 400 × (9/50)sec = 72 sec = 1 (12/60)min =

**1(1/6)min**####
**5. Question**

Tata Safari covers a distance of 550 meters in 1 minute whereas a Renault Duster covers a distance of 33 km in 45 minutes. The ratio of their speeds is:

**Solution**

Ratio of their speeds

Speed of Tata Safari = 550/60 × 18/5 = 33 km/hr

Speed of Renault Duster = 33 / 45 × 60 = 44 km/hr

Ratio of speeds = 33 : 44

Ratio of Speeds =

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A man traveled from the village to the post - office at the rate of 25 km/h and walked back at the rate of 4 km/h. If the whole journey took 5 hours 48 minutes. Find the distance of the post - office from the village.

First of all, we have to calculate average speed by applying the formula i.e. (2xy/x+y)

Average speed = (2 × 25 × 4) / (25 + 4)km/h = 200/29 km/h

As we know Distance = Speed × Time

Distance traveled in 5 hours 48 minutes =

Distance of Post Office from the village = 40 / 2 = 20 km

**3 : 4**

### Calculation of Distance in case of Speed Difference

Suppose a man covers a certain distance at x km/hr and an equal distance at y km/hr. Then, to find the average speed during the whole journey, following formula is applied.####
**6. Question**

A man traveled from the village to the post - office at the rate of 25 km/h and walked back at the rate of 4 km/h. If the whole journey took 5 hours 48 minutes. Find the distance of the post - office from the village.**Solution**First of all, we have to calculate average speed by applying the formula i.e. (2xy/x+y)

Average speed = (2 × 25 × 4) / (25 + 4)km/h = 200/29 km/h

As we know Distance = Speed × Time

Distance traveled in 5 hours 48 minutes =

Distance of Post Office from the village = 40 / 2 = 20 km