College

[tex]\[ = \frac{110 \times 2}{9} \, \text{km h}^{-1} = 24 \frac{4}{9} \, \text{km h}^{-1} \][/tex]

**EXERCISE 12(A)**

12.4) A motorist traveled the distance measured in meters in 10 minutes. Find his speed in 35 seconds. What is his speed in [tex]\(\text{km h}^{-1}\)[/tex]?

A racing car covered 600 km in 3 hours 20 minutes. Find its speed in meters per second.

A car covers a certain distance in 50 seconds. How much distance will the car cover in 50 seconds?

Rohit travels 350 km in 5 hours. Find:
(i) his speed
(ii) the distance covered by Rohit in 6.2 hours
(iii) the time taken by him to cover 210 km
[Assume that throughout the journey, the speed of Rohit remains uniform].

A boy drives his scooter with a uniform speed of [tex]\(45 \, \text{km h}^{-1}\)[/tex]. Find:
(i) the distance covered by him in 1 hour 20 minutes
(ii) the time taken by him to cover 108 km
(iii) the time taken to cover 900 m

Travel a distance of 10 km and come back in [tex]\(2 \frac{1}{2}\)[/tex] hours. What is my speed?

Answer :

Sure! Let's solve the given questions step-by-step.

### Problem Statement:
Rohit goes 350 km in 5 hours. Find:
1. (i) His speed
2. (ii) The distance covered by Rohit in 6.2 hours
3. (iii) The time taken by him to cover 210 km

Assume that throughout the journey, the speed of Rohit remains uniform.

### Step-by-Step Solution:
#### 1. Finding Rohit's Speed
Speed is defined as the distance traveled divided by the time taken.

Given:
- Distance traveled = 350 km
- Time taken = 5 hours

[tex]\[ \text{Speed} = \frac{\text{Distance}}{\text{Time}} = \frac{350 \text{ km}}{5 \text{ hours}} = 70 \text{ km/h} \][/tex]

Rohit's speed is [tex]\( 70 \text{ km/h} \)[/tex].

#### 2. Finding the Distance Covered by Rohit in 6.2 hours
Once the speed is known, we can calculate the distance for any given time using the formula:
[tex]\[ \text{Distance} = \text{Speed} \times \text{Time} \][/tex]

Given:
- Speed = 70 km/h (calculated above)
- Time = 6.2 hours

[tex]\[ \text{Distance} = 70 \text{ km/h} \times 6.2 \text{ hours} = 434 \text{ km} \][/tex]

The distance covered by Rohit in 6.2 hours is [tex]\( 434 \text{ km} \)[/tex].

#### 3. Finding the Time Taken to Cover 210 km
Using the relationship for time:
[tex]\[ \text{Time} = \frac{\text{Distance}}{\text{Speed}} \][/tex]

Given:
- Distance = 210 km
- Speed = 70 km/h (calculated above)

[tex]\[ \text{Time} = \frac{210 \text{ km}}{70 \text{ km/h}} = 3 \text{ hours} \][/tex]

The time taken by Rohit to cover 210 km is [tex]\( 3 \text{ hours} \)[/tex].

### Summary:
1. Rohit's speed is [tex]\( 70 \text{ km/h} \)[/tex].
2. The distance covered by Rohit in 6.2 hours is [tex]\( 434 \text{ km} \)[/tex].
3. The time taken by him to cover 210 km is [tex]\( 3 \text{ hours} \)[/tex].

If you have any further questions or need additional clarifications, feel free to ask!