Aptitude Questions and Answers
Devesh can cover a certain distance in 1 hour 24 minutes by covering two-third of the distance at 6 km/hour and the rest at 7 km/hr. Calculate total distance.
Let the total distance be x , then
`[{(2/3) x }/6 ] + [{(1/3) x }/7 ] = 7/5`
`=> x/9 + x/21 = 7/5`
`=> 7x = 63`
`=> x = 9`
Therefore , total distance = `6 km`
In covering a distance of 40 km, Kamlesh takes 2 hours more than Pankaj. If Kamlesh doubles his speed, then he would take 1 hour less than Pankaj. Then what is Kamlesh's speed?
Let Kamlesh’s speed be x km/hr.
Then, `40/x - 40/(2x) = 4`
8x = 40
x = 5 km/hr
If 120 km is done by train and the rest by car, then it takes 8 hours for a 600 km journey. Of 200 km is done by train and the rest by car, then it takes 20 minutes more. Then what would be the ratio of the speed of the train to that of the car?
Let speed of the train be x km/hr and of the car be y km/hr.
Then, `120/x + 480/y = 8`
=> `1/x + 4/y = 1/5` --- (i)
And, `200/x + 400/y = 25/3`
=> `1/x + 2/y = 1/24` --- (ii)
Solving (i) and (ii), we get x = 60 and y = 80.
Ratio of speeds = 60: 80 = 3:4
I walk a certain distance and ride the car back taking a total time of 33 Minutes. I could walk both sides in 45 min. How long would it take me to ride both ways?
Time taken in walking a certain distance from X and Y = 22 `1/2` Min
Time taken in riding the same distance = 33 - 22 `1/2` = 10 `1/2` Min
It will take 21 Min (10 `1/2` * 2) to ride both ways.
Avinash covers a distance of 8km in 50 minutes. If he covers 3km distance in 2/5th of time then, What speed should he maintain to cover the remaining distance in the remaining time?
Total distance = 8 Km
Total time = 50 minutes
Time taken to cover the distence of 3 Km = `50**(2/5) = 20 min = 1/3 hours`
Remaining distance = 8 - 3 = 5 Km
Required speed = `5/((1/3)) = 15 Kmph`
Jack takes 20 minutes to jog around the race course one time, and 25 minutes to jog around a second time. What is his average speed in miles per hour for the whole jog if the course is 3 miles long?
Average speed = total distance / total time
Total distance covered = 6 miles; total time = 45 minutes = 0.75 hours
Average speed = 6/ 0.75 = 8 miles/hour
A runs 25% faster than B and is able to allow B a lead of 7 meters to end a race in dead heat. What is the length of the race?
A runs 25% as fast as B.
That is, if B runs 100m in a given time, then A will run 125m in the same time
In other words, if A runs 5m in a given time, then B will run 4m in the same time.
Therefore, if the length of a race is 5m, then A can give B a start of 1m so that they finish the race in a dead heat.
Start : length of race :: 1 : 5
In this question, we know that the start is 7m.
Hence, the length of the race will be 7 * 5 = 35m.
Two trains running in opposite directions cross a man standing on the platform in 27 seconds and 17 seconds respectively and they cross each other in 23 seconds. The ratio of their speeds is:
Let the speeds of the two trains be x m/sec and y m/sec respectively.
Then, length of the first train = 27x metres, and length of the second train = 17y metres.
`(27x+17y)/(x+y) = 23`
27x + 17y = 23x + 23y
4x = 6y
`x/y = 3/2`
A person walks at 5kmph for 6hr and at 4km/h for 12hr. His average speed is ?
Answer : 1.
`"Avg speed" = "total distance"/"total time"`
= `((5*6) + (4*12)) / 18`
=`4 1/3` km/h
A man can cover a distance in 1hr 24min by covering 2/3 of the distance at 4 km/h and the rest at 5km/h. The total distance is
Answer : 4
Total time = 1hr 24min = 60min + 24 min = 84 min = `84/60`hours
Let total distance be S.
`"Time" = "Distance" / "Speed"`
`84/64 = ((2S)/3)/4 + (S/3)/5`
`84/64 = (S/6) + (S/15)`
`84/64 = (21S)/(6*15)`
`S = (84 * 6 * 15)/(64 * 21)`
S = 6km