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Q:

A man stands on the pan of a balance holding a fish in his right hand and bucket of water in his left hand. If he transfers the fish into the bucket, the total weight on the pan

A) increases	B) decreases
C) remains the same	D) first increases and then decreases

Answer & Explanation Answer: C) remains the same

Explanation:

Before transferring the fish, the position is the man with the fish and the bucket of water. After transferring the position is: the man without the fish, but the fish inside the water in the bucket. Thus to know whether there is any change in weight, it is enough to consider whether there is any change in weight when the fish in air is transferred into the water. The answer is there is no change as when in water though it loses weight due to upthrust of water on it, the level of water increases and exerts an equal force at the bottom.So, (c) is correct.

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Filed Under: Physics

Q:

A man stands in a lift which accelerates upwards. The resultant reaction force on the floor of the lift is

A) greater than the weight of the man	B) less than the weight of the man
C) Same as the weight of the man	D) Zero

Answer & Explanation Answer: A) greater than the weight of the man

Explanation:

The weight of the man mg is acting on the floor. As the lift is moving up with an acceleration, say a, the man too in it is having this acceleration. The force producing this acceleration is ma. By Newton's third law, this force will have an equal reaction pressing the floor equal to ma. Therefore the total resultant reaction on the floor is mg+ma = m(g+a) which is mg, the weight of the man. So (a) is correct.

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Filed Under: Physics

Q:

Two pipes A and B can fill a tank in 24 hours and $17 \frac{1}{7}$ hours respectively. Harihar opened the pipes A and B to fill an empty tank and some times later he closed the taps A and B , when the tank was supposed to be full. After that it was found that the tank was emptied in 2.5 hours because an outlet pipe "C" connected to the tank was open from the beginning. If Harihar closed the pipe C instead of closing pipes A and B the remaining tank would have been filled in :

A) 2 hours	B) 8 hours
C) 6 hours	D) 4 hours

Answer & Explanation Answer: B) 8 hours

Explanation:

Efficiency of Inlet pipe A = 4.16% $(\frac{100}{24})$

Efficiency of Inlet pipe B = 5.83% $(\frac{100}{17 \frac{1}{7}})$

Therefore, Efficiency of A and B together = 100 %

Now, if the efficiency of outlet pipe be x% then in 10 hours the capacity of tank which will be filled = 10 * (10 - x)

Now, since this amount of water is being emptied by 'C' at x% per hour, then

$\frac{10 x (10 - x)}{x} = 2.5 h r s$

=> x = 8

Therefore, in 10 hours 20% tank is filled only. Hence, the remaining 80% of the capacity will be filled by pipes A and B in 80/10 = 8 hours

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Filed Under: Time and Work
Exam Prep: AIEEE , Bank Exams , CAT
Job Role: Bank Clerk , Bank PO

Q:

A can do a piece of work in 10 days, B in 15 days. They work together for 5 days, the rest of the work is finished by C in two more days. If they get Rs. 3000 as wages for the whole work, what are the daily wages of A, B and C respectively (in Rs):

A) 200, 250, 300	B) 300, 200, 250
C) 200, 300, 400	D) None of these

Answer & Explanation Answer: B) 300, 200, 250

Explanation:

A's 5 days work = 50%

B's 5 days work = 33.33%

C's 2 days work = 16.66% [100- (50+33.33)]

Ratio of contribution of work of A, B and C = $50 : 33 \frac{1}{3} : 16 \frac{2}{3}$ = 3 : 2 : 1

A's total share = Rs. 1500

B's total share = Rs. 1000

C's total share = Rs. 500

A's one day's earning = Rs.300

B's one day's earning = Rs.200

C's one day's earning = Rs.250

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Filed Under: Time and Work
Exam Prep: CAT , Bank Exams , AIEEE
Job Role: Bank PO , Bank Clerk

Q:

A and B runs around a circular track. A beats B by one round or 10 minutes. In this race, they had completed 4 rounds. If the race was only of one round, find the A's time over the course:

A) 8 min	B) 7.5 min
C) 12.5 min	D) 12 min

Answer & Explanation Answer: B) 7.5 min

Explanation:

B runs around the track in 10 min.

i.e , Speed of B = 10 min per round

Therefore, A beats B by 1 round

Time taken by A to complete 4 rounds

= Time taken by B to complete 3 rounds

= 30 min

Therefore, A's speed = 30/4 min per round = 7.5 min per round

Hence, if the race is only of one round A's time over the course = 7 min 30 sec

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Filed Under: Time and Distance
Exam Prep: AIEEE , Bank Exams , CAT
Job Role: Bank Clerk , Bank PO

Q:

Two trains A and B start simultaneously in the opposite direction from two points P and Q and arrive at their destinations 16 and 9 hours respectively after their meeting each other. At what speed does the second train B travel if the first train travels at 120 km/h

A) 90 km/h	B) 160 km/h
C) 67.5 km/h	D) None of these

Answer & Explanation Answer: B) 160 km/h

Explanation:

$\frac{s_{1}}{s_{2}} = \sqrt{\frac{t_{2}}{t_{1}}}$

$\Rightarrow \frac{120}{s_{2}} = \sqrt{\frac{9}{16}} = \frac{3}{4}$

$\Rightarrow$ $s_{2} = 160 k m / h$

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Filed Under: Time and Distance

Q:

In a race of 800m Kaushik gives Piyush a start of 200m and then loses the race by 20 seconds. What is the speed of Piyush and Kaushik respectively ? If the ratio of respective speeds be 3:2.

Answer

Let the speed of Kaushik be Sk and speed of Piyush be Sp and let the time taken by Piyush be t second then,

$\frac{Sk}{Sp} = \frac{\frac{800}{t + 20}}{\frac{600}{t}} = \frac{2}{3} (since given ratio)$

t = 20 s

Speed of Piyush = Sp = 600/20 = 30 m/s

and Speed of Kaushik = 800/40 = 20 m/s

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Subject: Time and Distance Exam Prep: AIEEE , Bank Exams , CAT
Job Role: Bank Clerk , Bank PO

Q:

A fast moving superfast express crosses another pasenger train in 20 seconds. The speed of faster train is 72 km/hr and speeds of slower train is 27 km/h. Also the length of faster ntrain is 100m, then find the length of the slower train if they are moving in the same direction.

A) 100 m	B) 125 m
C) 150 m	D) 175 m

Answer & Explanation Answer: C) 150 m

Explanation:

$T i m e = \frac{S u m o f l e n g t h o f t h e t w o t r a i n s}{D i f f e r e n c e i n s p e e d s}$

$20 = \frac{(100 + x)}{\frac{25}{2}}$

$\Rightarrow$ X=150m

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Filed Under: Logarithms

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