12
Q:

# How long will a boy take to run round a square field of side 35 meters, If he runs at the rate of 9 km/hr?

 A) 50 sec B) 52 sec C) 54 sec D) 56 sec

Explanation:

Speed = 9 km/hr =     ${\color{Blue}&space;\left&space;(&space;9\times&space;\frac{5}{18}&space;\right&space;)&space;m/sec&space;=\frac{5}{2}m/sec}$

Distance = (35 x 4) m = 140 m.

Time taken =${\color{Blue}&space;\left&space;(&space;140\times&space;\frac{2}{5}&space;\right&space;)&space;sec&space;=56&space;sec}$

Q:

Two trains start from same place at same time at right angles to each other. Their speeds are 36km/hr and 48km/hr respectively. After 30 seconds the distance between them will be ?

 A) 900 mts B) 300 mts C) 250 mts D) 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.

3 55
Q:

An employee may claim Rs. 7.00 for each km when he travels by taxi and Rs. 6.00 for each km if he drives his own car. If in one week he claimed Rs. 595 for traveling 90 km. How many kms did he travel by taxi ?

 A) 55 kms B) 35 kms C) 25 kms D) 65 kms

Explanation:

Let x and y be the respective km's travelled by man via taxi and by his own car.
Given x + y = 90 => x = 90 - y
But according to the question,
7x + 6y = 595
7(90-y) + 6y = 595
=> 630 - 7y + 6y = 595
=> y = 630 - 595 = 35
=> x = 90 - 35 = 55
Therefore, the distance travelled by taxi is 55 kms.

4 33
Q:

K is 50% faster than L. If L starts at 9 A.M. and K starts at 10 A.M. L travels at a speed of 50 km/hr. If L and K are 300 kms apart, The time when they meet when they travel in opposite direction is ?

 A) 12 pm B) 1 pm C) 11 am D) 11:30 am

Explanation:

let 't' be the time after which they met since L starts.

Given K is 50% faster than L

50 t + 1.5*50(t-1) = 300

50 t +75 t = 300 + 75

t = 375 / 125 = 3 hrs past the time that L starts

So they meet at (9 + 3)hrs = 12:00 noon.

3 67
Q:

A goods truck travels from a place at a certain time and at fixed speed. After 6hrs another truck leaves the same place and move in same direction of uniform speed of 90kmph. The truck catches up the goods truck in 4hrs. Find the speed of the goods truck ?

 A) 36 kmph B) 32 kmph C) 28 kmph D) 34 kmph

Explanation:

Let the speed of goods truck be 'p' kmph
Distance covered by goods truck in 10hrs (4+6) = Distance covered by other truck in 4 hrs.
10p = 4 x 90
p = 36kmph.
Therefore, the speed of the goods truck is p = 36 kmph.

3 35
Q:

A man covers a distance of 1200 km in 70 days resting 9 hours a day, if he rests 10 hours a day and walks with speed 1½ times of the previous in how many days will he cover 840 km ?

 A) 39 days B) 37 days C) 35 days D) 33 days

Explanation:

Distance d = 1200km
let S be the speed

he walks 15 hours a day(i.e 24 - 9)
so totally he walks for 70 x 15 = 1050hrs.

S = 1200/1050 => 120/105 = 24/21 => 8/7kmph

given 1 1/2 of previous speed
so 3/2 * 8/7= 24/14 = 12/7

New speed = 12/7kmph

Now he rests 10 hrs a day that means he walks 14 hrs a day.

time = 840 x 7 /12 => 490 hrs
=> 490/14 = 35 days

So he will take 35 days to cover 840 km.