1. How many seconds will a 500 meter long train moving with a speed of 63 km/hr, take to cross a man walking with a speed of 3 km/hr in the direction of the train ?
1. 42
2. 50
3. 30
4. 28
Answer & Explanation Answer:- 3 Explanation :- Relative Speed = 63 – 3 = 60 Km/h = 60 *(5/18) = 50/3 m/sec 2. A boat covers a distance of 30 km downstream in 2 hours while it takes 6 hours to cover the same distance upstream. How much time the boat will take to cover 90 km in still water? Answer & Explanation Answer:- 2 Explanation :- Upstream speed = 30/ 6 km/hr = 5km/h 3. Car A and B travel to a place at a speed of 35 and 55 km/h respectively. If car B takes 3.5 hours less time than A for the journey, the distance of the place is_ Answer & Explanation Answer:- 4 Explanation :- Speed of Car A = 35 km/h Speed of Car B = 55 km/h 4. A dog takes 3 leaps for every 5 leaps of a hare. If one leap of the dog is equal to 3 leaps of the hare, the ratio of the speed of the dog to that of the hare is Answer & Explanation Answer:- 2 Explanation :- Dog : Hare = (3*3) leaps of hare : 5 leaps of hare = 9 : 5 5. Two trains of equal lengths take 10 seconds and 15 seconds respectively to cross a telegraph post. If the length of each train be 120 metres, in what time (in seconds) will they cross each other travelling in opposite direction? Answer & Explanation Answer:- 3 Explanation :- Speed of train 1 = (120/10) = 12 m/sec
Time Taken to pass the man = Distance/Speed
= 500/(50/3) = 30 sec
1. 6 hrs
2. 9 hrs
3. 15 hrs
4. None of these
5. Data inadequate
Downstream speed = 30/2 km/hr = 15 km/h
Speed of boat in still water = (5 + 15)/2 = 10 km/hr
Required time = 90/10 = 9 hrs
1. 300.25 km
2. 400 km
3. 350.565 km
4. 336.875 km
5. None of these
Let time taken by Car A = t
Speed = Distance/Time
35 = Distance/t & 55 = Distance/(t-3.5)
Distance = 35t & Distance = 55(t-3.5)
Therefore , 35t = 55(t-3.5)
t = 77/8
Distance = 35 * 77/8 = 336.87 km
1. 4:5
2. 9:5
3. 8:5
4. 9:2
1. 10
2. 15
3. 12
4. 20
Speed of train 2 = (120/15) = 8 m/sec
As they are moving in opposite direction
Therefore ,
Relative speed = 12 + 8 = 20 m/sec
Distance covered = 120 + 120 = 240 m
Time = distance/speed = 240/20 = 12 sec