Solve these questions to crack the SI exams

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.   If a person travelled at 56 km/hr instead of 48 km/hr, he would have travelled 40 km more in same time. Find […]

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.

 

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1. If a person travelled at 56 km/hr instead of 48 km/hr, he would have travelled 40 km more in same time. Find the actual distance travelled by him?

Solution:

S1 = 48 km/hr                    S2 = 56 km/hr

D1 = x km                            D2 = (x + 40) km

T   = x/48 hrs                       T  =  x+40/56 hrs

Both the cases, time is same

So  => 56x = 48x + 1920

8x = 1920

X = 240 km.

Simple Method:

Increased Speed              = 56 – 48 = 8 km/hr

Increased Distance          = 40 km/hr

Time                                      = 40 / 8 = 5 hrs

Actual Distance                 = 5 × 48 = 240 km

2. The distance between A and B is 650 km. A person travelled from A to B at 60 km/hr and started at 9 am and another person travelled from B to A at 70 km/hr and started at same time. Then at what time they meet together?

Solution:

Both persons are started at same time

Let 9 am after ‘x’ hours, they meet together

So the sum of distance covered by 1^st person in ‘x’ hours and distance covered by second person in ‘x’ hours should be equal to 650 km

60x + 70x = 650

130x = 650

X = 5 hrs

9 am after 5 hours means 2 pm

At 2 pm, they meet together.

Simple Method:

Relative Speed = 60 + 70 = 130 km/hr

Distance               = 650 km

Time                      = 650 / 130 = 5 hours

9 am after 5 hours means 2 pm

3. The distance between A and B is 490 km. A person travelled from ‘A’ to ‘B’ 40 km/hr and started at 9 am, after one hour another person travelled from ‘B’ to ‘A’ at 50 km/hr. Then what time they meet together?

Solution:

Both the persons are not started at same time.

Let 9 am after ‘x’ hours, they meet together.

So the sum of distance covered by 1^st person in ‘x’ hours and distance covered by second person in ‘x – 1’ hours should be equal to 490 km

40x + 50(x – 1)   = 490

40x + 50x – 50    = 490

90x                         = 540

X                             = 6 hours

X = 6 hrs

9 am after 6 hours means 3 pm

At 3 pm, they meet together.

Simple Method:

Relative Speed = 40 + 50 = 90 km/hr

First one hours, the distance covered by first person = 40 km

Now starting time            = 10 am

Remaining Distance        = 490 – 40 = 450 km

So Distance                         = 450 km

Time                                      = 450 / 90 = 5 hours

10 am after 5 hours means 3 pm

4. A carcan travel 50% faster than a bike. Both start from point A at the same time and reach point B 540kms away from A at the same time. On the way, however, the car lost about 3 hours while stopping at the restaurant. Fine the speed of the Bike?

Solution:

D             = 540 km

Let speed of bike             = x km/hr

Speed of car                       = 3x/2 km/hr

According to the question

X = 60 km/hr

Speed of the Bike = 60 km/hr

5. The ratio between the speeds of two bikes is 3 : 4. If the second bike runs 480 km in 6 hours, then find the speed of the first bike?

Solution:

Second bike speed          = 480/6 = 80 km/hr

Let first bike speed         = x km/hr

So 3 : 4 = x : 80

4x = 3 × 80

X = 60 km/hr

Speed of the first bike = 60 km/hr

6. A person travelled at 30 m/s and reached his destination in 4 hours. Find the distance?

Solution:

Time      = 4 hours

Speed   = 30 m/s

Speed is there in m/s, so first convert speed from m/s to km/hr

Speed   = 30 × 18/5 = 90 km/hr

Distance               = 4 × 90 = 360 km

Banda Ravipal Reddy

Director, SIGMA

Sai Institute of General Mental Ability

Hyderabad