Time and distance. Numerical Reasoning . Test 02
- A train covers a distance in 50 min, if it runs at a speed of 48kmph on an average. The speed at which the train must run to reduce the time of journey to 40min will be.Time=50/60 hr=5/6hr
Speed=48mph
distance=S*T=48*5/6=40km
time=40/60hr=2/3hr
New speed = 40* 3/2 kmph= 60kmph - )A man covers a distance on scooter. Had he moved 3kmph faster he would have taken 40 min less. If he had moved 2kmph slower, he would have taken 40min more. The distance is.Let distance = x m
Usual rate = y kmph
x/y – x/y+3 = 40/60 hr
2y(y+3) = 9x ---------------------------------(1)
x/y-2 – x/y = 40/60 hr y(y-2) = 3x -----------(2)
divide 1 & 2 equations
by solving we get x = 40 km - A motorist covers a distance of 39km in 45min by moving at a speed of x kmph for the first 15min, then moving at double the speed for the next 20 min, and then again moving at his original speed for the rest of the journey. Find x.Total distance = 39 km
Total time = 45 min
D = S*T
x * 15/60 + 2x * 20/60 + x * 10/60 = 39 km
x = 36 kmph - A & B are two towns. A person covers the distance from A to B on cycle at 17kmph and returns to A by a boat running at a uniform speed of 8kmph. His average speed for the whole journey isWhen same distance is covered with different speeds, then the average speed = 2xy / x+y = 10.88kmph
- A car covers 4 successive 3km stretches at speed of 10kmph, 20kmph, 30kmph & 60kmph resp. Its average speed isAverage speed = total distance / total time
total distance = 4 * 3 = 12 km
total time = 3/10 + 3/20 + 3/30 + 3/60
= 36/60 hr
speed =12/36 * 60 = 20 kmph - A bullock cart has to cover a distance of 80km in 10hrs. If it covers half of the journey in 3/5th time. what should be its speed to cover the remaining distance in the time left.Time left = 10 - 3/5*10
= 4 hr 10 km/h
speed =40 km /4 hr
=10 kmph - The ratio between the speeds of the A& B is 2:3, and therefore A takes 10 min more than the time taken by B to reach the destination. If A had walked at double the speed, he would have covered the distance inRatio of speed = 2:3
Ratio of time = 3:2
A takes 10 min more
3x-2x = 10 min
A time=30 min
-> covers the distance in 30 min , if its speed is x
-> He will cover the same distance in 15 min, if its speed
doubles (i.e 2x) - A train M leaves City A at 5 am and reaches City B at 9am . Another train N leaves City B at 7am and reaches City A at 1030am. At what time do the 2 trains cross one another?Let the distance between the cities be x
They meet after y hr after 7am
M covers x in 4hr
N covers x in 3 ½ i.e 7/2 hr
speed of M =x/4
speed of N = 2x/7
Distance covered by M in y+2 hr + Distance covered by N in
y hr is x
x/4 (y+2) +2x/7(y)=x
y=14/15hr or 56 min - A man takes 5hr 45min in walking to certain place and riding back. He would have gained 2hrs by riding both ways. The time he would take to walk both ways is?Let x be the speed of walked
Let y be the speed of ride
Let D be the distance
Then D/x + D/y = 23/4 hr -------------------(1)
D/y + D/y = 23/4 – 2 hr
D/y = 15/8 ----------------------------------(2)
substitute 2 in 1
D/x + 15/8 = 23/4
D/x = 23/4 -15/8 =46-15/8 =31/8
Time taken for walk one way is 31/8 hr
time taken to walk to and fro is 2*31/8 = 31/4 hr
=7 hr 45 min - A person crosses a 600 m long street in 5 minutes. What is his speed in km per hour?Speed=(600/5 * 60) m/sec
= 2 m/sec.
Converting m/sec to km/hr
=(2*18/5) km/hr
= 7.2 km/hr.
Score: 0 /
10
Today's running total: 0