The respective ratio between the speed of a bike, a van and lorry is 3 : 5 : 2. The speed of the van is 250 percent of the speed of the lorry which covers 360 km in 12 hours. What is the average speed of the bike and the van together?

Correct Answer: 8 hrs

Explanation:

Given speed of the bike after servicing = 55 kmph

Time taken for travelling some distance at 55 kmph = 5 hrs

Then, 

Distance = Speed x Time = 55 x 5 = 275 kms.

Now, 

Speed of the bike before servicing = 35 kmph

Distance = 275 kms

Now, Time = Distance/Speed = 275/35 = 7.85 hrs =~ 8 hrs.

Correct Answer: Option B

Explanation:

Man walked 6 km at 1.5 kmph, again he walked 8 km at speed of 2 kmph and 40 km at a speed of 8kmph
time taken indivisually:
=> 6/1.5 = 4 m
=> 8/2 = 4 m
=> 40/8 = 5 m

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Average speed of man= total distance/ total time
=> 54/13 =  4 2 13 kmph

Correct Answer: 204 m

Explanation:

To find the minimum distance, we have to get the LCM of 75, 80, 85

Now, LCM of 75, 80, 85 = 5 x 15 x 16 x 17 = 20400

Hence, the minimum distance each should walk so that thay can cover the distance in complete steps = 20400 cms = 20400/100 = 204 mts.

Correct Answer: 75 km/h , 100 km/h

Explanation:

Let Pele x km in 1 hour. so Maradona takes (2h-40min)=1 h 20 min to cover x km. Let speed of Maradona and Pele be M and P respectively than 

                            x =M x (4/3)  and x= P x 1

  => M/P = 3/4 

 Again       300 M = 300 P = 1

? 300 3 k - 300 4 k = 1 

 => k= 25

  M= 3k = 75 km/h   and   P= 4k = 100 km/h 

( Through options it is very easy to solve)

Correct Answer: 8

Explanation:

u = k , v= 3k 

 

? 2 u v u + v ? 2 × k × 3 k k + 3 k = 12  => k = 8km/h

Correct Answer: 32 sec

Explanation:

Given that,

1st train speed = 62 km/hr 

2nd train speed  = 44 km/hr

Hence the relative speed of two trains is : 62-44 = 18 km/hr = 18 × 5 18 m/s = 5 m/s.

There fore, the first train crosses the second train i.e (85+75)mts of distance with a speed of 5m/s in, 

 

time =  d i s tan c e s p e e d = 85 + 75 5 = 32 sec.

Correct Answer: 500 mts

Explanation:

Using pythagarous theorem,
distance travelled by first train = 36x5/18x30 = 300m
distance travelled by second train = 48x5/18x30 = 400m
so distance between them =?( 90000 + 160000) = ?250000 = 500mts.

Correct Answer: 4 km/hr

Explanation:

Let P's speed = x km/hr. Then, Q's speed = (7 - x) km/ hr.

 

So, 24/x + 24/(7 - x) = 14

 

x 2 - 98x + 168 = 0

 

(x - 3)(x - 4) = 0 => x = 3 or 4.

 

Since, P is faster than Q,

 

so P's speed = 4 km/hr and Q's speed = 3 km/hr.

Correct Answer: 41.25 days

Explanation:

Given Karthik can cover the distance of 200 kms resting 2 hrs per day in 22 days.

 

Let the initial speed be '1'

 

Hence, Time = 22(24hrs - 2)

 

Noe new speed = 2/3

 

Let the number of days he take be 'D'

 

Therefore,  22 24 - 2 x 3 200 = D 24 - 2 x 2 250

 

D = 11 x 3 x 5/4 = 41.25 days. = 41 1/4 days.

Correct Answer: 24 kmph

Explanation:

Let the speed of the train be 'S' kmph

From the given data,

Distance = Length of train = D = 200 mts = 200 x 18/5 kms

Time = 10 sec

given speed of the motorcycler = 12 kmph

Relative speed as they are moving in the same direction = (S - 12) kmph

$$\begin{gathered} ( S - 12) = 200 x 18 5 15 \\ S - 12 = 48 \\ S = 60 kmph \\ \end{gathered}$$

Hence, the speed of the train = S = 60 kmph

Now,

Let the speed of the jeep be 'x' kmph

$$\begin{gathered} 60 - x = 200 x 18 5 20 \\ 60 - x = 36 \\ x = 60 - 36 \\ x = 24 kmph \end{gathered}$$

 

Therefore, the speed of the jeep = x = 24 kmph.