24 Feb

image 1In some way or the other most candidates remain overly concerned about their performance on quantitative aptitude section of the competitive exam they are taking. For many candidates the problem starts from the basic level: lack of concept clarity.  Even those whose concepts are relatively clear may lag behind in terms of speed that is required to attempt exam questions.

To address these concerns it is fairly common for candidates engaged in IBPS Clerk Exam Preparation to join Bank Exam Coaching Centres in Delhi or even their hometowns. However, even those who have enrolled themselves in various institutes experience difficulty in cracking Time, Speed & Distance questions. These questions are often left un-attempted because they are considered lengthy and quite time consuming. However, this should no longer be the case because Maths experts at Vidya Guru Institute have presented out here the shortcuts and tricks that they discuss in their classes.

Basic Concepts:
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The fundamental concept of Speed is defined as the Distance travelled divided by Time elapsed during motion. You must understand that when Time is constant, the Distance travelled will be directly proportional to Speed. In the exam, you will be asked to find out the values of one or more of these variables using the information given.

Shortcut Trick:

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If a man decreases his Speed from usual, he reaches late & if he increases his Speed from usual, he reaches early, then the Distance can be easily calculated by:
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Question: 1 On walking at the Speed of 5 kmph a boy reaches his school 10 minutes late, but if he walks at the Speed of 6 kmph he reaches 10 minutes early then how far is his school (in kms)?

Solution: 10 kms
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Question: 2 On walking at the Speed of 30 kmph a boy reaches his school 10 minutes late, but if he walks at the Speed of 40 kmph he reaches school 4 minutes late, then

(a) How far is his school (in kms)?

(b) Find the usual Time taken (in minutes) by him to reach his school.

Solution:
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(b) Usual Time can be found by either of the 2 cases given in the question.

Usual Time = Distance / Speed

In the 1st case, it is mentioned that on walking at the Speed of 30 kmph, he reaches his school 10 minutes late. Time taken in the 1st case = Distance / Speed = 12 kms / 30 kmph = 0.4 hr = 0.4 minutes = 24 minutes.

In this case, we also know that he is 10 minutes late. This means the scheduled Time for him was = 24-10 = 14 minutes

Question: 3 A man driving his bike at the Speed of 24 kmph reaches his office 5 minutes late. Had he driven 25% faster on an average he would have reached 4 minutes earlier than the scheduled Time. Find out the following:

(a) The Distance of his office

(b) The usual Time taken (in minutes) by him to reach his school.

(c) His usual Speed (in kmph)

Solution:
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(b) Usual Time = Distance / Speed

In the 1st case, it is mentioned that on walking at the Speed of 24 kmph a man reaches his office 5 minutes late.

Time taken in the 1st case = Distance / Speed = 18 kms / 24 kmph = 3/4 hr = 0.75 minutes = 45 minutes.

In this case, we also know that he is 5 minutes late, it means scheduled Time for him was = 45- 5 = 40 minutes.

(c) Usual Speed = Distance / Time = 18 kms / 40 minutes

= 18 km 60 / 40 hr   = 27 kmph

Question: 4 In covering a Distance of 30 kms, Abhay takes 2 hours more than Sameer. If Abhay doubles his Speed, then he would take 1 hour less than Sameer. Abhay’s Speed is:

Solution: 5 kmph
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Question: 5 A passenger train takes two hours less for a journey of 300 km if its Speed is increased by 5 kmph from its normal Speed. The normal Speed is

Solution: 25 kmph
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But the Speed cannot be negative. So, the Speed of the passenger train is 25 kmph.

Having gone through the problems illustrated above, you now know how to apply these shortcut tricks. However, you must practice more questions which will improve your level of confidence apart from ensuring that you score a couple of marks from this particular area. For this practice you may refer to any standard textbook on objective Maths or even the online study material offered by different portals.

Summary:

As a candidate engaged in IBPS PO or SSC CGL Preparation, this blog will be of definite help to you. In case, you require further academic support from Vidya Guru faculty members, you can write at vidyagurudelhi@gmail.com.

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