Mohan plans to travel to his village which is 300 km. He plans to travel 20% of the journey first by car and remaining by train. The speed of the train and car is 80 km/hr and 60 km/hr respectively. Mohan travelled first 20% by car but as he reached the railway station he missed the train and decides to travel all the distance by car so he increases the speed and reaches on time. What percent should be the increase in speed of the car so as to reach on time?

Mohan plans to travel to his village which is 300 km. He plans to travel 20% of the journey first by car and remaining by train. The speed of the train and car is 80 km/hr and 60 km/hr respectively. Mohan travelled first 20% by car but as he reached the railway station he missed the train and decides to travel all the distance by car so he increases the speed and reaches on time. What percent should be the increase in speed of the car so as to reach on time? Correct Answer 33.33%

Given:

Distance between his current position to village is 300 km

Speed of the train = 80 km/hr

Formula Used:

Speed = Distance/time

Calculation:

Let Increased speed of car be y km/hr

Speed of the train = 80 km/hr

In the first case,

Distance travelled by car =  20% of 300 km = 60 km

Distance travelled by train =  80% of 300 km = 240 km

Time taken for the journey

t1 = = 60/60 + 240/80     ---(1)

In the second case,

Distance travelled by car = 300 km

Time taken for the journey

t2 = 60/60 + 240/y       ----(2)

As the time taken is equal in both cases, then

From equation (1) & (2)

60/60 + 240/80 = 60/60 + 240/y

⇒ 3 = 240/y 

⇒ y = 80 km/hr 

∴ Percentage Increase in the speed = (80 - 60)/60 × 100 = 33.33%

Confusion PointsIt is given that when he misses the train he decides to cover the whole journey with his car. So, it is clearly depicted that he must be travelling initially with the speed given in the question initially.

Related Questions

Each of the question below consists of a question and three statements number I, II and III given below it. You have to decide whether the data provided in the statement are sufficient to answer the question. If the bus is travelling from Surat to Ahmadabad and a car is travelling from Ahmadabad to Surat, then what is the distance between Surat and Ahmadabad? I. The speed of a car is 40% less than the speed of bus. Bus started at 9 am and car started at 10 am and they meet at 3 pm of the same day. II. After travelling for 1 hour, because of traffic average speed of bus is decreased by 20% and covers distance between Surat to Ahmadabad in 11 hours. Original speed of car is 20% less than original speed of bus and before crossing bus it covered 200 km if starts 1 hour later than bus. After crossing car, bus covers remaining distance in 5 hours. III. Speed of bus is 10 km/hr more than the speed of car and before crossing car ratio of distances covered bus and car in same time was 5 : 4. Time taken by car to cover the distance between Ahmadabad and Surat is 2 hours 15 minutes more than time taken by bus to cover the same distance.