# Quantitative Aptitude > Time and Distance

 Refresher Test 2 - Time and Distance Discuss Refresher Test - Time and Distance Discuss

Practice Tests
 Practice Test - Time and Distance Discuss

Speed

Free Online Preparation for CAT 2009 with Minglebox e-CAT Prep. Cover basic concepts of Time and Distance under Quantitative Aptitude for MBA Entrance Exam Preparation with Study material, solved examples and tests prepared by CAT coaching experts.

Speed is the rate at which distance is covered by a moving body these speed

's' = or

s =

if speed is constant then

if distance is constant then

if time is constant then

Average speed

Average speed. If a body cover half of the distance 'd' it a speed of and  the half at speed then average speed is given by

= =

Relative speed

The time taken by a train of length 'l' moving with speed 's' to pare a pole is

=

Time taken by train of length 'l' moving with speed 's' to completely pare a platform of

length 'd' =

Time taken by strain of length 'l' moving with speed to par another train of length 'd' moving with speed in the direction (provided

) =

Time taken by a train, of length l, and moving with speed to pan another train of length 'd' moving with in the opposite direction

If person covers a certain distance 'd' moving speed and taking time , then the person covers the same distance moving at speed

and taking time then

If two persons X and Y start at the same time in opposite direction from two places and arrive at their respective destination in x an y hours later after having met on their on their way then

If speed of boat, in still water is 'a' (m/s) then speed of boat in going down stream in a river which is following at 'b' (m/s) is (a+b) m/s. Hence if a boat cover a certain distance 'd' downstream and then reruns it to its staring point covering the same distance 'd' then

Circular races

If 2 persons say a,b start running a race on a circular track, then the faster runner (say A) will be together with the slower runner for the
first time when faster runner has gained one complete length of the track or round over the slower runner.

Solved Examples

Question

2boats A and B start from point P at the same constant speed of 15 km/hr in still water . Boat A goes to Q, where boat B goes till R, which is equidistant from P and Q and returns to P. If the time taken by boat A is 1.5 times that of B, what is the speed of the current.

1. 10 k mph

2. 7.5 k mph ,

3. 5k mph

4. Data insufficient

Solution

If the total distance between P and Q be '2D' km . Boat A has taken more time , the direction of the current must be form Q to P if the speed of the current must be X k mph then

Time taken by A =

Time taken by B =

Given

Solving we get x = 7.5 k mph have option 2 is the right option.

Question

A car covers half the half distance at speed 60kmph and another half of the distance at speed 30kmph . Find the average speed of the car for the whole journey?

Solution

If total distance be '2d' then time taken to cover the first half of the journey , =

and time taken to cover the second half of the journey =

Therefore total time taken    =

Avg .Speed = =

Question

A car cover travels for half the time of the journey at speed 60kmph and another half of the time at 30kmph. Find the average speed of the car for whole journey?

Solution

Let the total time taken in for the journey be '2t' then distance covered in firat half of the journey = and distance covered in

second half of the journey

Average speed =

Hence average speed of for the whole journey = 45kmph

Question

Two persons A and B walk from X to Y a distance of 27 k  at 5 km/hr and 7 km/hr respectively. B reaches Y and immediately turns back meeting A at Z. What is the distance from X to Z ?

1. 25 km

2. 22.5 km

3. 24 km

4. 20 km

Solution

Let the distance from X to Z be 'a' km then time taken by X to cover distance XZ is same as time taken by B to cover distance XY – YZ = 27 + 27-a

Time Taken by A to cover XZ distance XZ =

Time taken by B to cover distance XY – XZ =

solving we get, a = 22.5 km

 Refresher Test 2 - Time and Distance Discuss Refresher Test - Time and Distance Discuss

 Practice Test - Time and Distance Discuss

dhanraj77115 : oops atul u have to find avrage speed different distance is not given distance will b same as it consider as d

dhanraj77115 : average speed formula is correct; atul, u have learnt same bt another method formula
this formula is more simple to calculate average

vani9719 : yeah,anki is true

suresh3302 : In the final question.....together A & B will travel a distance of 54 which will be covered by A & B in the ration 5 : 7.

Now distance XZ is nothing but the share of A which will be 5/12 (54) = 22.5

ankita7231 : ankita-pls include some toughest problems also

mayur3839 : add some more practise paper.....bt overall gud

baljinder874 : gud

atul2777 : 1 mistake in the formula:
Average speed. If a body cover half of the distance 'd' it a speed of and the half at speed then average speed is given by

total dist/total time= 2d/{(d1/s1)+d2/s2}

madydilse : please check the tests there are some mistakes in the questions...