Quantitative Aptitude - Arithmetic Ability Questions

Q:

Two boys starting from the same place walk at a rate of 5kmph and 5.5kmph respectively. What time will they take to be 8.5km apart, if they walk in the same direction?

A) 15 hours B) 16 hours
C) 17 hours D) 18 hours
 
Answer & Explanation Answer: C) 17 hours

Explanation:

In this type of questions we need to get the relative speed between them,
The relative speed of the boys = 5.5kmph – 5kmph
= 0.5 kmph

Distance between them is 8.5 km
Time = Distance/Speed
Time= 8.5km / 0.5 kmph = 17 hrs

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Filed Under: Time and Distance
Exam Prep: GRE

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Q:

16 children are to be divided into two groups A and B of 10 and 6 children. The average percent marks obtained by the children of group A is 75 and the average percent marks of all the 16 children is 76. What is the average percent marks of children of group B ?

A) 233/3 B) 243/4
C) 254/5 D) 345/7
 
Answer & Explanation Answer: A) 233/3

Explanation:

 Required average = [(76 * 16) - (75 * 10)] / 6 = (1216 - 750)/6 = 466/3 = 233 /3.

 

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Filed Under: Average

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Q:

Consider the word ROTOR. Whichever way you read it, from left to right or from right to left, you get the same word. Such a word is known as palindrome. Find the maximum possible number of 5-letter palindromes.

A) 17756 B) 17576
C) 12657 D) 12666
 
Answer & Explanation Answer: B) 17576

Explanation:

The first letter from the right can be chosen in 26 ways because there are 26 alphabets.

 

Having chosen this, the second letter can be chosen in 26 ways

 

The first two letters can chosen in 26 x 26 = 676 ways

 

Having chosen the first two letters, the third letter can be chosen in 26 ways.

 

All the three letters can be chosen in 676 x 26 =17576 ways.

 

It implies that the maximum possible number of five letter palindromes is 17576 because the fourth letter is the same as the second letter and the fifth letter is the same as the first letter.

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Q:

The year next to 2003 will have the same calendar as that of the year 2003?

A) 2024 B) 2014
C) 2009 D) 2020
 
Answer & Explanation Answer: B) 2014

Explanation:

Given year 2003, when divided by 4 leaves a remainder of 3.

NOTE: When remainder is 3, 11 is added to the given year to get the result.

So, 2003 + 11 = 2014

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Filed Under: Calendar

36 16262
Q:

What is the total surface area of a right circular cone of height 14 cm and base radius 7 cm?

A) 344.35 sq.cm B) 462 sq.cm
C) 498.35 sq.cm D) None of these
 
Answer & Explanation Answer: C) 498.35 sq.cm

Explanation:

h = 14 cm, r = 7 cm.  

So, l =72+142 = 245 = 75cm   

Total surface area = πrl+πr2 = 227×7×75 + 227×7×7 

=1545+1 

= (3.236 x 154) sq.cm   

= 498.35 sq.cm

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Q:

There are 5 novels and 4 biographies. In how many ways can 4 novels and 2 biographies can be arranged on a shelf ?

A) 26100 B) 21600
C) 24000 D) 36000
 
Answer & Explanation Answer: B) 21600

Explanation:

4 novels can be selected out of 5 in 5C4 ways.

2 biographies can be selected out of 4 in 4C2 ways.

Number of ways of arranging novels and biographies = 5C4*4C2  = 30

After selecting any 6 books (4 novels and 2 biographies) in one of the 30 ways, they can be arranged on the shelf in 6! = 720 ways.

By the Counting Principle, the total number of arrangements = 30 x 720 = 21600

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Q:

A man whose speed is 4.5 kmph in still water rows to a certain upstream point and back to the starting point in a river which flows at 1.5 kmph, find his average speed for the total journey ?

A) 5 kmph B) 7 kmph
C) 3 kmph D) 4 kmph
 
Answer & Explanation Answer: D) 4 kmph

Explanation:

Speed of Man = 4.5 kmph
Speed of stream = 1.5 kmph
Speed in DownStream = 6 kmph
Speed in UpStream = 3 kmph
Average Speed = (2 x 6 x 3)/9 = 4 kmph.

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

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Q:

What is the least number of squares tiles required to pave the floor of a room 15 m 17 cm long and 9 m 2 cm broad ?

A) 844 B) 814
C) 840 D) 820
 
Answer & Explanation Answer: B) 814

Explanation:

Length of largest tile = H.C.F. of 1517 cm and 902 cm = 41 cm.
Area of each tile = (41 x 41) sq.cm

Required number of tiles =1517 x 902/(41 x 41) = 814.

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Filed Under: Area
Exam Prep: AIEEE , Bank Exams , CAT
Job Role: Bank Clerk

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