Quantitative Aptitude - Arithmetic Ability Questions

Q:

The first 8 alphabets are written down at random. what is the probability that the letters b,c,d,e always come together ?

A) 1/7 B) 8!
C) 7! D) 1/14
 
Answer & Explanation Answer: D) 1/14

Explanation:

The 8 letters can be written in 8! ways.
n(S) = 8!
Let E be the event that the letters b,c,d,e always come together when the first 8 alphabets are written down.
Now the letters a, (bcde), f, g and h can be arranged in 5! ways.
The letters b,c,d and e can be arranged themselves in 4! ways.
n(E) = 5! x 4!
Now, the required P(E) = n(E)/n(S) = 5! x 4!/8! = 1/14
Hence the answer is 1/14. 

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Filed Under: Probability
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15 8640
Q:

What is the value of 100P2 ?

A) 10000 B) 9900
C) 8900 D) 7900
 
Answer & Explanation Answer: B) 9900

Explanation:

Here in 100P2, P says that permutations and is defined as in how many ways 2 objects can be selected from 100 and can be arranged.

 

That can be done as,

 

100 P2  = 100!/(100 - 2)!

= 100 x 99 x 98!/98!

= 100 x 99 

= 9900.

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Filed Under: Permutations and Combinations
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8 8630
Q:

A fraction becomes 2/3 when 1 is added to both, its numerator and denominator .And , it becomes 1/2 when 1 is subtracted from both the numerator and denominator. What is the fraction?

Answer

Let required fraction be  then 


           ............. (i)


and          ............ (ii)


Solving (i) and (ii) we get x=3, y=5


\inline \therefore Required fraction = 

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16 8630
Q:

The price of 2 oranges, 3 bananas and 4 apples is Rs. 15. The price of 3 oranges, 2 bananas and 1 apple is Rs. 10. What will be price of 4 oranges, 4 bananas and 4 apples  ?

A) Rs. 10 B) Rs. 15
C) Rs. 20 D) Rs. 25
 
Answer & Explanation Answer: C) Rs. 20

Explanation:

Let the Oranges be 'O', Bananas be 'B' and Apples be 'A'

From the given data,

 

2O + 3B + 4A = 15 ...... (I)

3O + 2B + A = 10 ..... (II)

On adding (I) and (II),

5O + 5B + 5A = 25

O + B + A = 5

4O + 4B + 4A = 20.

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Filed Under: Simplification
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12 8625
Q:

Three graziers A,B and C rent a piece of pasture for a month. A puts in 27 cattle for 19 days, B 21 for 17 days and C 24 for 23 days. If at the end of the month the rent amount to Rs.237, how much ought to be paid by each.

Answer

A's cattle = 27 x 19 = 513


B's cattle = 21 x 17 = 357


C's cattle = 24 x 23 = 552


Ratio of cattle = 513 : 357 : 552


                    = 171 : 119 : 184


 


payment to be made by A = \inline 237\times \frac{171}{474}


                                     = Rs.85.50


payment to be made by B = \inline 237\times \frac{119}{474}


                                     = Rs.59.50


payment to be made by C = \inline 237\times \frac{184}{474}


                                     = Rs.92

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Subject: Partnership

7 8616
Q:

A sector of 120, cut out from a circle, has an area of 667cm2. Find the radius of the circle ?

A) 1 B) 2
C) 3 D) 4
 
Answer & Explanation Answer: C) 3

Explanation:

Let the radius of the circle be r cm. Then, 

 

120360πr2=667 

 

r2=667*722*3 

 

r=3.

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Filed Under: Area
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2 8608
Q:

Ajay who is a King, at his eleventh hour, called his three queens and distributed his gold in the following way: He gave 50% of his wealth to his first wife, 50% of the rest to his second wife and again 50% of the rest to his third wife. If their combined share is worth1,30,900 kilograms of gold, find the quantity of gold King Ajay was having initially?

A) 153145 kgs B) 147890 kgs
C) 152400 kgs D) 149600 kgs
 
Answer & Explanation Answer: D) 149600 kgs

Explanation:

Let the total quantity of gold be p kgs.

According to the question,

50% of p + 25% of p + 12.5% of p = 130900

87.5% of p = 130900

p = 130900 x 100/87.5  = 149600 kgs.

 

Therefore, the initial gold quantity that king has = p = 149600 kgs.

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7 8607
Q:

854*854*854-276*276*276854*854+854*276+276*276=?

A) 546 B) 578
C) 607 D) None of these
 
Answer & Explanation Answer: B) 578

Explanation:

Given exp . is like this 854*854*854-276*276*276854*854+854*276+276*276=?

 

so ans = 854 - 276 = 578

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Filed Under: Numbers

3 8605