Bank PO Questions


Q:

A box contains 4 different black balls, 3 different red balls and 5 different blue balls. In how many ways can the balls be selected if every selection must have at least 1 black ball and one red ball ?

A) 24 - 1  

B) 2425-1   

C) (24-1)(23-1)25   

D) None 

A) A B) B
C) C D) D
 
Answer & Explanation Answer: C) C

Explanation:

It is explicitly given that all the 4 black balls are different, all the 3 red balls are different and all the 5 blue balls are different. Hence this is a case where all are distinct objects.

 

Initially let's find out the number of ways in which we can select the black balls. Note that at least 1 black ball must be included in each selection.

 

Hence, we can select 1 black ball from 4 black balls
or 2 black balls from 4 black balls.
or 3 black balls from 4 black balls.
or 4 black balls from 4 black balls.

 

Hence, number of ways in which we can select the black balls

 

= 4C1 + 4C2 + 4C3 + 4C4
= 24-1 ........(A)

 

Now let's find out the number of ways in which we can select the red balls. Note that at least 1 red ball must be included in each selection.

 

Hence, we can select 1 red ball from 3 red balls
or 2 red balls from 3 red balls
or 3 red balls from 3 red balls

 

Hence, number of ways in which we can select the red balls
= 3C1 + 3C2 + 3C3
=23-1........(B)

 

Hence, we can select 0 blue ball from 5 blue balls (i.e, do not select any blue ball. In this case, only black and red balls will be there)
or 1 blue ball from 5 blue balls
or 2 blue balls from 5 blue balls
or 3 blue balls from 5 blue balls
or 4 blue balls from 5 blue balls
or 5 blue balls from 5 blue balls.

 

Hence, number of ways in which we can select the blue balls
= 5C0 + 5C1 + 5C2 + … + 5C5
= 25..............(C)

 

From (A), (B) and (C), required number of ways
=  2524-123-1

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Filed Under: Permutations and Combinations
Exam Prep: GATE , CAT , Bank Exams , AIEEE
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3 9406
Q:

Two trains namely X & Y leave station 'A' at 6.30am and 7.40am and travel at 30km/hr and 40 km/hr respectively. How many kms from 'A' will the trains meet ?

A) 140 kms B) 120 kms
C) 96 kms D) 142 kms
 
Answer & Explanation Answer: A) 140 kms

Explanation:

It is given train X leave station A at 6:30 am, here it is asked to calculate the distance from A when the trains meet, the
Distance traveled by train left at 6:30 am upto 7:40 am i.e. in 1 hr. 10 min. or 7/6 hours = 30 x 7/6 = 35 km
So train leaving at 7:40 am will meet first train after covering a distance of 35 km. with relative speed of 40-30=10 km/hr.
Hence time taken = 35/10 = 3.5 hours or 3 hours 30 minutes
So distance from A = Distance traveled by 2nd train in 3 hr. 30 min
= 40 x 3.5 = 140 km.

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Filed Under: Problems on Trains
Exam Prep: AIEEE , Bank Exams , CAT , GATE , GRE
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15 9406
Q:

Find the remainder when 1234 x 1235 x 1237 is divided by 8.

A) 4 B) 2
C) 0 D) 6
 
Answer & Explanation Answer: D) 6

Explanation:

When we divide 1234 by 8, remainder is 2

When we divide 1235 by 8, remainder is 3

When we divide 1237 by 8, remainder is 5

---> 2 x 3 x 5 = 30 

As 30 will not be the remainder because it is greater than 8,

when 30 divided by 8, remainder = 6.

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Filed Under: Numbers
Exam Prep: CAT
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7 9405
Q:

There is an empty reservoir whose capacity is 30 litres. There is an inlet pipe which fills at 5 L/min and there is an outlet pipe which empties at 4 L/min. Both the pipes function alternately for 1 minute. Assuming that the inlet pipe is the first one to function, how much time will it take for the reservoir to be filled up to its capacity?

A) 49.5 min B) 50 min
C) 51 min D) 52 min
 
Answer & Explanation Answer: C) 51 min

Explanation:

The work to be done = Capacity of reservoir  = 30 litres.

 1st Minute ---> inlet pipe opened ---> 5 lit filled

 2nd minute ---> inlet pipe closed; outlet pipe opened ---> 4 lit emptied

 

In 2 minutes (5 litres - 4 litres = 1lit) is filled into the reservoir.

It takes 2 minutes to fill 1lit ---> it takes 50 minutes to fill 25 litres into the reservoir.  

 

In the 51st minute inlet pipe is opened and the reservoir is filled.

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Filed Under: Pipes and Cistern
Exam Prep: CAT
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24 9399
Q:

The famous book Kankal is authored by ?

A) Ketan Bhagat B) Mahesh Rao
C) Nirmal Verma D) Jaishankar Prasad
 
Answer & Explanation Answer: D) Jaishankar Prasad

Explanation:
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Filed Under: Books and Authors
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23 9397
Q:

Foresight : Anticipation :: Insomnia : ?

A) Gems B) Sleeplessness
C) Iron D) Diamond
 
Answer & Explanation Answer: B) Sleeplessness

Explanation:

The words in each pair are synonyms. Here Foresight and Anticipation are synonyms to each other and Insomnia is a synonym to Sleeplessness.

 

Hence, Foresight : Anticipation :: Insomnia : Sleeplessness.

 

 

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Filed Under: Analogy
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9 9395
Q:

A spreadsheet contains

A) Rows B) Columns
C) Both A & B D) Tables
 
Answer & Explanation Answer: C) Both A & B

Explanation:

A_spreadsheet_contains1553603758.png image

 

A spreadsheet contains both rows and columns.

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Filed Under: Computer
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5 9391
Q:

Ashok Mehta committee recommended for the establishment of

A) Gram Panchayat B) Nagar Panchayat
C) Panchayat Samiti D) All of the above
 
Answer & Explanation Answer: A) Gram Panchayat

Explanation:

Under the chairmanship of Ashoka Mehta, the Janata Government appointed a committee on Panchayat Raj system in December 1977. They have made 132 recommendations to revive and strengthen the declining Panchayati Raj system in the country. As a result of this report, the Indian states of Karnataka, Andhra Pradesh, and West Bengal passed new legislation.

Ashok_Mehta_committee_recommended_for_the_establishment_of1560945557.jpg image

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Filed Under: Indian Politics
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4 9387