Speed, Time & Distance — Multiple Choice Questions

A speed of 15 m/s is the same as:

1. 45 km/hr

2. 48 km/hr

3. 54 km/hr

4. 60 km/hr

Answer

To convert a speed of m/sec into km/hr, we multiply by $\dfrac{18}{5}$.

15 m/s = $\left(15 \times \dfrac{18}{5}\right)$ km/hr = 54 km/hr

Hence, option 3 is the correct option.

A speed of 90 km/hr is the same as:

1. 25 m/s

2. 30 m/s

3. 36 m/s

4. 27 m/s

Answer

To convert a speed of km/hr into m/s, we multiply by $\dfrac{5}{18}$.

90 km/hr = $\left(90 \times \dfrac{5}{18}\right)$ m/s = 25 m/s

Hence, option 1 is the correct option.

A car covers a distance of 7 km in 5 minutes. Its speed is:

1. 70 km/hr

2. 63 km/hr

3. 84 km/hr

4. 105 km/hr

Answer

Given,

Distance covered = 7 km

Time taken = 5 minutes

= $\dfrac{5}{60} \text{ hr } = \dfrac{1}{12}$ hr

By formula,

$\text{Speed} = \dfrac{\text{Distance}}{\text{Time}} = \dfrac{7 \text{ km}}{\dfrac{1}{12} \text{ hr}}\\[1em] = 7 \times 12 \text{ km/hr }\\[1em] = 84 \text{ km/hr }$

Hence, option 3 is the correct option.

A motorcyclist travels at 30 m/s. How much distance does he cover in 15 minutes?

1. 24 km

2. 27 km

3. 30 km

4. 36 km

Answer

Given,

Speed = 30 m/s

Time taken = 15 min = (15 × 60) sec = 900 sec

By formula,

$\text{Distance} = \text{Speed} \times \text{Time}\\[1em] = 30 \times 900 \text{ m }\\[1em] = 27000 \text{ m }\\[1em] = \dfrac{27000}{1000} \text{ km } = 27 \text{ km }$

Hence, option 2 is the correct option.

A motorbike covers 84 km in 2 hrs 24 min. The speed of the bike is:

1. 50 km/hr

2. 45 km/hr

3. 40 km/hr

4. 35 km/hr

Answer

Given,

Distance covered = 84 km

Time taken = 2 hrs 24 min

= $2\dfrac{24}{60} \text{ hrs } = 2\dfrac{2}{5} \text{ hrs } = \dfrac{12}{5}$ hrs

By formula,

$\text{Speed} = \dfrac{\text{Distance}}{\text{Time}} = \dfrac{84 \text{ km}}{\dfrac{12}{5} \text{ hrs}}\\[1em] = 84 \times \dfrac{5}{12} \text{ km/hr }\\[1em] = 35 \text{ km/hr }$

Hence, option 4 is the correct option.

A car runs at a speed of 90 km/hr. What distance does it cover in 50 minutes?

1. 72 km

2. 75 km

3. 52 km

4. 65 km

Answer

Given,

Speed = 90 km/hr

Time taken = 50 minutes

= $\dfrac{50}{60} \text{ hr } = \dfrac{5}{6}$ hr

By formula,

$\text{Distance} = \text{Speed} \times \text{Time}\\[1em] = 90 \times \dfrac{5}{6} \text{ km }\\[1em] = 75 \text{ km }$

Hence, option 2 is the correct option.

A car is running at 20 m/s. How much distance will it cover in 2 hrs 20 min.?

1. 175 km

2. 172 km

3. 168 km

4. 165 km

Answer

Given,

Speed = 20 m/s

Time taken = 2 hrs 20 min

= $2\dfrac{20}{60} \text{ hrs } = 2\dfrac{1}{3} \text{ hrs } = \dfrac{7}{3}$ hrs

Converting the speed into km/hr :

20 m/s = $\left(20 \times \dfrac{18}{5}\right)$ km/hr = 72 km/hr

By formula,

$\text{Distance} = \text{Speed} \times \text{Time}\\[1em] = 72 \times \dfrac{7}{3} \text{ km }\\[1em] = 24 \times 7 \text{ km }\\[1em] = 168 \text{ km }$

Hence, option 3 is the correct option.

Which of the following is the slowest speed?

1. 45 km/hr

2. 10 m/s

3. 0.9 km/min.

4. all are equal

Answer

To compare the speeds, we convert each of them into km/hr.

10 m/s = $\left(10 \times \dfrac{18}{5}\right)$ km/hr = 36 km/hr

0.9 km/min = (0.9 × 60) km/hr = 54 km/hr

Since, 36 km/hr < 45 km/hr < 54 km/hr

⇒ 10 m/s is the slowest speed.

Hence, option 2 is the correct option.

A car travels at 90 km/hr. How much distance does it cover in 8 seconds?

1. 160 m

2. 200 m

3. 240 m

4. 250 m

Answer

Given,

Speed = 90 km/hr

Time taken = 8 seconds

Converting the speed into m/sec :

90 km/hr = $\left(90 \times \dfrac{5}{18}\right)$ m/s = 25 m/s

By formula,

$\text{Distance} = \text{Speed} \times \text{Time}\\[1em] = 25 \times 8 \text{ m }\\[1em] = 200 \text{ m }$

Hence, option 2 is the correct option.