Quantitative Aptitude - Arithmetic Ability Questions

Q:

An alloy of copper and bronze weight 50g. It contains 80% Copper. How much copper should be added to the alloy so that percentage of copper is increased to 90%?

A) 45 gm B) 50 gm
C) 55 gm D) 60 gm
 
Answer & Explanation Answer: B) 50 gm

Explanation:

Initial quantity of copper =80100 x 50 = 40 g 

And that of Bronze = 50 - 40 = 10 g

Let 'p' gm of copper is added to the mixture

=> 50 + p x 90100 = 40 + p

=> 45 + 0.9p = 40 + p

=> p = 50 g

Hence, 50 gms of copper is added to the mixture, so that the copper is increased to 90%.

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Filed Under: Alligation or Mixture
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20 7005
Q:

If the radius of a circle is decreased by 50% , find the percentage decrease in its area.

A) 75% B) 65%
C) 35% D) 25%
 
Answer & Explanation Answer: A) 75%

Explanation:

let original radius = r and  new radius = (50/100) r = r/2

 


original area = πr2 and new area = πr/22

 


decrease in area =  3πr2/4*1πr2 *100 = 75%

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Filed Under: Area
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0 7003
Q:

In a public bathroom there are n taps 1,2,3...n. Tap1 and Tap2 take equal time to fill the tank while Tap3 takes half the time taken by Tap2 and Tap4 takes half the time taken by Tap3. Similarly each next number of tap takes half the time taken by previous number of Tap i.e, K-th Tap takes half the time taken by (K-1)th Tap. If the 10th tap takes 2 hours to fill the tank alone then what is the ratio of  efficiency of 8th tap and 12th tap, respectively?

A) 4:1 B) 5:3
C) 16:1 D) 1:16
 
Answer & Explanation Answer: D) 1:16

Explanation:

Time taken by 8th tap = 2 x 2 x 2= 8 hours

Time taken by 12th tap = 2x (1/2) x (1/2)  = 1/2 hour

Ratio of time taken by 8th tap and 12th tap = 8 : 1/2 =16:1

Therefore, Ratio of efficiencies of 8th tap and 12th tap =1:16

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Filed Under: Time and Work

8 6986
Q:

Cost Price of 22 articles is same as the Selling Price of 18 articles, find the profit percentage?

A) 33.33% B) 22.22%
C) 11.11% D) 1%
 
Answer & Explanation Answer: B) 22.22%

Explanation:

Let the cost price of 1 article = Rs. 1

From the given data,

Then, the selling price of 1 article = 22/18 = 11/9

Then, Profit = SP - CP = 11/9 - 1 = 2/9

Required, profit % = Profit/CP x 100

= [(2/9)/1] x 100

= 200/9

= 22.222%.

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Filed Under: Profit and Loss
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11 6982
Q:

In how many different ways can five persons stand in a line for a group photograph?

A) 120 B) 240
C) 360 D) 720
 
Answer & Explanation Answer: A) 120

Explanation:

This is the number of permutations of five things taken all at a time.

 

Therefore, answer = 5P5 = 120 ways

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2 6967
Q:

Solve the equation 122x+1 = 1 ?

A) -1/2 B) 1/2
C) 1 D) -1
 
Answer & Explanation Answer: A) -1/2

Explanation:

Rewrite equation as 122x+1 = 120

 

Leads to 2x + 1 = 0 

 

Solve for x : x = -1/2

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Filed Under: Logarithms
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Q:

Two persons Shyam and Rahim can do a job in 32 days together. Rahim can do the same job in 48 days alone. They started working together and after working 8 days Rahim is replaced by a third person Ram whose efficiency is half that of Rahim. Find in how many days the remaining work will be completed by both Shyam and Ram together?

A) 16 days B) 72/5 days
C) 15 days D) 96/5 days
 
Answer & Explanation Answer: B) 72/5 days

Explanation:

Work done by Shyam and Rahim in 8 days = 8/32 = 1/4

Remaining work to be done by Shyam and Ram = 1 - 1/4 = 3/4

Given efficieny of Ram is half of Rahim i.e, as Rahim can do the work in 48 days, Ram can do the work in 24 days.

One day work of Ram and Shyam = (1/32 - 1/48) + 1/24 = 5/96

Hence, the total work can be done by Shyam and Ram together in 96/5 days.

 

Therefore, remaining work 3/4 can be done by them in 3/4 x 96/5 = 72/5 = 14.4 days.

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Filed Under: Time and Work
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Q:

Rohith started a business by investing Rs. 3600. After somedays, Puneeth joined him by investing Rs. 2400. At the end of one year, the profit was divided in the ratio 2 : 1. After how many months did Puneeth join the business?

A) 2 months B) 2.5 months
C) 3 months D) 3.5 months
 
Answer & Explanation Answer: C) 3 months

Explanation:

Ratio of profit of Rohith and Puneeth = 3600 x 12 : 2400 x P

= 3600 x 12/2400P = 2/1

=> P = 9

So, Puneeth joined the business after (12 - P) = 12 - 9 = 3 months.

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Filed Under: Partnership
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