Quantitative Aptitude - Arithmetic Ability Questions

Q:

Three taps P, Q and R can fill a tank in 12 hrs, 15 hrs and 20 hrs respectively. If P is open all the time and Q and R are open for one hour each alternately, starting with Q, then the tank will be full in how many hours ?

A) 9 hrs B) 7 hrs
C) 13 hrs D) 11 hrs
 
Answer & Explanation Answer: B) 7 hrs

Explanation:

Given,

P can fill in 12 hrs

Q can fill in 15 hrs

R can fill in 20 hrs

=> Volume of tank = LCM of 12, 15, 20 = 60 lit

=> P alone can fill the tank in 60/12 = 5 hrs

=> Q alone can fill the tank in 60/15 = 4 hrs

=> R alone can fill the tank in 60/20 = 3 hrs

Tank can be filled in the way that

(P+Q) + (P+R) + (P+Q) + (P+R) + ....

=> Tank filled in 2 hrs = (5+4) + (5+3) = 9 + 8 = 17 lit

=> In 6 hrs = 17 x 6/2 = 51 lit

=> In 7th hr = 51 + (5+4) = 51 + 9 = 60 lit

=> So, total tank will be filled in 7 hrs.

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

11 10967
Q:

If P(A)=4/9;then the odd against the event A is:

A) 4:9 B) 4:5
C) 5:4 D) 4:14
 
Answer & Explanation Answer: C) 5:4

Explanation:

Here,P(A)=4/9=p/(p+q)

P(odd against event A)=q/p=5/4

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Filed Under: Probability

11 10961
Q:

The inner circumference of a circular race track, 14m wide is 440m. Find the radius of the outer circle.

A) 84m B) 24m
C) 44m D) 54m
 
Answer & Explanation Answer: A) 84m

Explanation:

let inner radius be r meters. 

2πr=440r=440×744=70mradius of outer circle =70+14m  

 

Therefore, Radius of outer circle = 70 + 14 = 84m

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Filed Under: Area
Exam Prep: Bank Exams
Job Role: Bank PO

5 10953
Q:

If a positive integer n, divided by 5 has a remainder 2, which of the following must be true?

A) n is odd B) n + 1 cannot be a prime number
C) (n + 2) divided by 7 has remainder 2 D) n + 3 is divisible by 5
 
Answer & Explanation Answer: D) n + 3 is divisible by 5

Explanation:

You can find the integers which when divided by 5 have a remainder 2 by adding 2 to all multiples of 5. So we have n = 7 , 12, 17, 22 etc.

From this series we can see that n does not have to be odd.

Also n + 1 can be a prime because, for example, 12 + 1 = 13

And (n + 2) / 7 has a remainder 2 in some cases but not all.

Remember the question asks us for what MUST be true, and we see that none of the statements are true in all cases. However, adding 3 to any of the values of n will always give a multiple of 5.

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Filed Under: Numbers
Exam Prep: GRE

4 10937
Q:

What is the number of digits in 333? Given that log3 = 0.47712?

A) 12 B) 13
C) 14 D) 15
 
Answer & Explanation Answer: B) 13

Explanation:

 Let   Let x=333 333

 

 Then, logx = 33 log3  

 

= 27 x 0.47712 = 12.88224 

 

Since the characteristic in the resultant value of log x is 12

 

The number of digits in x is (12 + 1) = 13 

 

Hence the required number of digits in 333is 13.

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Filed Under: Logarithms
Exam Prep: AIEEE , Bank Exams , CAT
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49 10937
Q:

Twenty times a positive integer is less than its square by 96. What is the integer ?

A) 42 B) 36
C) 48 D) 24
 
Answer & Explanation Answer: D) 24

Explanation:

Let the integer be x. Then,

x2 - 20x = 96

(x + 4)(x - 24) = 0

x = 24

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Filed Under: Simplification
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12 10934
Q:

The average of 26,29,n,35 and 43 lies between 25 and 35. If n is always an integer and greater than the average  of the given integers then the value of n is :

A) 33 B) 34
C) 33 D) None of these
 
Answer & Explanation Answer: C) 33
Explanation:

Average of 26,29,35 and 43 is 33.25 . Also the average of 26 , 29, n, 35 and 43 lies between 25 and 35 i.e,

 25<26+29+n+35+435<35 

=> 125 < 26+29+n+35+43 < 175 

=> 125 < 133 + n < 175

=> n < 42

 Since the value of n is an integer and greater than 33.25 then 33 < n < 42 for every integer n.

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Filed Under: Average

9 10918
Q:

Rs 1000 is being  charged at 50% per annum. what is the interest for 3rd year at compound interest?

A) 1122 B) 1025
C) 1125 D) 625
 
Answer & Explanation Answer: C) 1125

Explanation:

Total amount for two years =  1000×1.52=2250

 Now , interest for third year = 2250×50×1100=1125

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Filed Under: Compound Interest

16 10912