Quantitative Aptitude - Arithmetic Ability Questions

Q:

 A pupil's marks were wrongly entered as 83 instead of 63. Due to that the average marks for the class got increased by half. The number of pupils in the class is :

A) 45 B) 40
C) 39 D) 37
 
Answer & Explanation Answer: B) 40

Explanation:

Let there be x pupils in the class.

Total increase in marks = (x * 1/2) = x/2.

x/2 = (83 - 63) => x/2 = 20 => x = 40.

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Filed Under: Average

197 81841
Q:

P can complete a work in 12 days working 8 hours a day.Q can complete the same work in 8 days working 10 hours a day. If both p and Q work together,working 8 hours a day,in how many days can they complete the work?

A) 60/11 B) 61/11
C) 71/11 D) 72/11
 
Answer & Explanation Answer: A) 60/11

Explanation:

P can complete the work in (12 x 8) hrs = 96 hrs 

Q can complete the work in (8 x 10) hrs=80 hrs 

Therefore, P's 1 hour work=1/96   and Q's 1 hour work= 1/80

(P+Q)'s 1 hour's work =(1/96) + (1/80) = 11/480. So both P and Q will finish the work in 480/11 hrs  

Therefore, Number of days of 8 hours each = (480/11) x (1/8) = 60/11

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Filed Under: Time and Work

236 81835
Q:

Simplify the following equation.

1943 + 12 + 13 + 11 + 14

A) 43/19 B) 1
C) 38/19 D) None of these
 
Answer & Explanation Answer: D) None of these

Explanation:

After solving we get,

 

62/931.

 

None of the options satisfy.

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

23 81703
Q:

Tea worth of Rs. 135/kg & Rs. 126/kg are mixed with a third variety in the ratio 1: 1 : 2. If the mixture is worth Rs. 153 per kg, the price of the third variety per kg will be____?

A) Rs. 169.50 B) Rs.1700
C) Rs. 175.50 D) Rs. 180
 
Answer & Explanation Answer: C) Rs. 175.50

Explanation:

Since first second varieties are mixed in equal proportions, so their average price = Rs.(126+135)/2= Rs.130.50

So, Now the mixture is formed by mixing two varieties, one at Rs. 130.50 per kg and the other at say Rs. 'x' per kg in the ratio 2 : 2, i.e., 1 : 1. We have to find 'x'.

 

Cost of 1 kg tea of 1st kind         Cost of 1 kg tea of 2nd kind 

 

 

  

x-153/22.50 = 1  => x - 153 = 22.50  => x=175.50.

 Hence, price of the third variety = Rs.175.50 per kg.

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Filed Under: Alligation or Mixture
Exam Prep: CAT , Bank Exams , AIEEE

555 81577
Q:

The missing number in the Series

114, 131, 165, 216,  ?, 369

 

A) 314 B) 304
C) 294 D) 284
 
Answer & Explanation Answer: D) 284

Explanation:

114       131     165     216     ?      369

   +17      +34     +51     +68    +85

 

=> The missing number in the given Number series = 216 + 68 = 284.

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Filed Under: Odd Man Out
Exam Prep: AIEEE , Bank Exams , CAT , GATE , GRE
Job Role: Analyst , Bank Clerk , Bank PO , Database Administration , IT Trainer

7 81222
Q:

Find the next number in the series 125, 80, 45, 20, ....

 

A) 5 B) 15
C) -5 D) 10
 
Answer & Explanation Answer: A) 5

Explanation:

The pattern is -45, -35, -25, -15

The next number = 20-15= 5

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

44 79647
Q:

Two pipes A and B can fill a tank in 15 minutes and 20 minutes respectively. Both the pipes are opened together but after 4 minutes, pipe A is turned off. What is the total time required to fill the tank?

A) 10 min. 20 sec. B) 11 min. 45 sec.
C) 12 min. 30 sec. D) 14 min. 40 sec.
 
Answer & Explanation Answer: D) 14 min. 40 sec.

Explanation:

Part filled in 4 minutes =4(1/15+1/20) = 7/15

 

Remaining part =(1-7/15) = 8/15

 

Part filled by B in 1 minute =1/20 : 8/15 :: 1:x 

x = (8/15*1*20) = 1023min = 10min 40sec

The tank will be full in (4 min. + 10 min. + 40 sec.) = 14 min. 40 sec

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Filed Under: Pipes and Cistern

193 79588
Q:

If the sum of two numbers is 55 and the H.C.F. and L.C.M. of these numbers are 5 and 120 respectively, then the sum of the reciprocals of the numbers is equal to:

A) 55/601 B) 601/55
C) 11/120 D) 120/11
 
Answer & Explanation Answer: C) 11/120

Explanation:

Let the numbers be a and b.

 

Then, a + b = 55 and ab = 5 x 120 = 600.

 

The required sum =1a+1b = a+bab55600=11120

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Filed Under: HCF and LCM

134 79481