SSC CGL Exam (Tier I): Study Material-Quantitative Aptitude: Time and Distance Concept

Staff Selection Commission conducts Combined Graduate Level Exam for recruitment to the different posts. The question paper for CGL Exam comprises 4 sections including General Intelligence and Reasoning, General Awareness, Quantitative Aptitude and English Comprehension. Jagranjosh has brought topic wise study material for ever section in which important topics will be covered. The Questions in the Quantitative Segment are aimed to test the ability of appropriate use of numbers. The scope of the test will be computation of whole numbers, decimals, fractions & relationships between numbers; percentage & ratio, time & distance; profit, loss & discount; graphs of linear equations; basic algebraic identities; pie chart; trigonometric ratio, geometry etc.

Time & Distance

Time and Distance Formulas relate Time, Distance and Speed. These relationships have several practical applications. It is observed that in all the Competitive Exams, questions based on the concept of Time & Distance are asked.

For example if you know the speed of any vehicle and the distance covered by that vehicle, then we can easily calculate the time taken in whole journey by using the formula of Time and Distance.

Important Formulas
Speed = Distance/Time ,Distance= Speed×Time, Time= Distance/Speed
S km/hr =(s×5/18)m/sec
S m/sec =(s×18/5)km/hr

Example

Taj Express travelling at 5/11 of its actual speed covers 42 km in 1 hr 40 min 48 sec. Find the actual speed of the Taj Express.

Solution

Suppose the actual speed of Taj = S km/hr
Then new speed =  5/11× S
Time taken by Taj with new speed
 = 1 hr 40 min 48 sec
= 1hr+40 × 1/60 hr+48 × 1/(60×60)  [Because 1hr = 60 minutes,
                                                        1 minute =  60 Second,
                                                        & 1 minute = ( 1)/60  hr ,
                                                        1 Second =  1/60 minute ]                 
                                               
= 1hr +2/3 hr + 1/75 hr
= 126/75 hrs
Now, according to the formula
New Speed × Time taken by Taj with new speed = Distance covered by Taj
 5/11 S× 126/75 = 42
 S = (42×75×11)/(126×5)
 S =55km/hr
Hence, the actual speed of the Taj Express is 55 km/hr

Points to remember about Time and Distance Segment Problems-

1. Read the units of time speed and distance carefully.
2. If the distance is given in km and the aped is in m/s then always convert the units. According to the demand of the question you can change the kilometer in to meter or m/s in to km /hr.

If you have any Question/Point on the above information, please ask/discuss it in the SSC Group