Practise questions for SI examinations

Hyderabad: This article is in continuation to the last article on preparation for the Sub-Inspector of Police recruitment exam. Here are some practice questions and solutions on the Time and Distance topic. 1. A person travelled 1440 km in 20 hours find his speed? Solution: S = 1440 / 20 = 72 km/hr Two options […]

Hyderabad: This article is in continuation to the last article on preparation for the Sub-Inspector of Police recruitment exam. Here are some practice questions and solutions on the Time and Distance topic.

1. A person travelled 1440 km in 20 hours find his speed?
Solution:

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S = 1440 / 20 = 72 km/hr
Two options are there in m/s, so convert speed from km/hr to m/s

S = 72 × 5/18 = 20 m/s
2. In covering a distance of 240 km, Sunil takes 3 hours more than Madhu. If Sunil doubles his speed, then he would take 1 hour less than Madhu. Then find the speed of Sunil?
Solution:

Let Sunil’s speed = x km/hr
Then 240/x – 240/2x = 4

240/2x = 4
120/x = 4
x = 30
Therefore, speed of Sunil = 30 km/hr
3. Robert is travelling on his cycle and has calculated to reach point A at 2 pm, if he travels at 10 kmph. He will reach there at 12 noon if he travels at 15 kmph. At what speed must he travel to reach A at 1 pm?
Solution:
Let the distance = x km

So x/10 – x/15 = 2 =>; (3x-2x)/30 = 2

x = 60 km

Time taken to travel 60 km at 10 km/hr = 60/ 10 = 6 hours

So, Robert started 6 hours before 2 pm. i.e., at 8 am

He should reach at 1 pm means, the time will be 5 hours

Therefore, the required speed = 60/5 = 12 km/hr

4. A person travelled a distance of 92 km in 10 hours. He travelled partly on foot at 5 km/hr and partly on bicycle at 12 km/hr. Then find the distance travelled on foot?

Solution:

Let the distance travelled on foot be ‘x’ km.
Then, distance travelled on bicycle = (92 -x) km.
So x/5 92 -x/12 = 10
12x 460 – 5x = 600
7x = 140
x = 20
=>; the distance travelled on foot = 20 km.
5. By travelling at 40 kmph, a person reaches his destination on time. He covered two-third of the total distance in one-third of the total time. What speed should he maintain for the remaining distance to reach his destination on time?

Solution:

Speed = 40 km/hr
Let Time = x hrs

So Distance = 40x km
Covered Distance = 2/3 × 40x = (80x /3)km
Covered Time = x/3 hrs

Remaining Distance = 40x – 80x/3 = (40x/3) km
Remaining Time = 2x/3hrs
Required Speed = 40x/3 × 3/2x = 20 km/hr

6. A boy travelled from his house to school at 3 km/hr, and he reaches 9 minutes late, next day he travelled at 4 km/hr, and he reaches 6 minutes early. Then find the distance between house and school?
Solution:
Let Distance = x km

If the boy reaches the school on time, the time taken = x minutes

First day journey time = (x 9) minutes

Second day journey time = (x – 6) minutes

Difference between two days Journey time = (x 9) – (x – 6) = 15 min = ¼ hours

So x/3 – x/4 = 1/4

x = 3 km

7. A man decided to cover a distance of 6 km in 84 minutes. He decided to cover two thirds of the distance at 4 km/hr and the remaining at some different speed. Find the speed after the two third distance has been covered.
Solution:
Distance = 6 km

Time = 84 min

2/3 of Distance = 2/3 × 6 = 4 km, Speed = 4 km/hr
Time = 4/4 = 1 hour = 60 minutes

So remaining time = 84 – 60 = 24 minutes = 24/60 = 2 / 5 hours

Remaining distance = 6 – 4 = 2 km

The required speed = 2 × 5/2 = 5 km/hr

Banda Ravipal Reddy
Director, SIGMA

Sai Institute of General Mental Ability

Hyderabad