6500+ Quantitative Aptitude Questions and Answers With Explanation

Q:

4 kg of a metal contains 1/5 copper and rest in Zinc. Another 5 kg of metal contains 1/6 copper and rest in Zinc.The ratio of Copper and Zinc into the mixture of these two metals:

A) 49 : 221	B) 39:231
C) 94:181	D) None of these

Answer & Explanation Answer: A) 49 : 221

Explanation:

Copper in 4 kg = 4/5 kg and Zinc in 4 kg = 4 x (4/5) kg

Copper in 5 kg = 5/6 kg and Zinc in 5 kg = 5 x (5/6) kg

Therefore, Copper in mixture = $\frac{4}{5} + \frac{5}{6} = \frac{49}{30}$ kg

and Zinc in the mixture = $\frac{16}{5} + \frac{25}{6} = \frac{221}{30}$ kg

Therefore the required ratio = 49 : 221

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Filed Under: Alligation or Mixture

30 17749

Q:

What is the smallest number by which 2880 must be divided in order to make it into a perfect square ?

A) 2	B) 3
C) 4	D) 5

Answer & Explanation Answer: D) 5

Explanation:

By trial and error method, we get
2880/3 = 960 is not a perfect square
2880/4 = 720 is not a perfect square
2880/5 = 576 which is perfect square of 24
Hence, 5 is the least number by which 2880 must be divided in order to make it into a perfect square.

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Filed Under: Numbers
Exam Prep: AIEEE , Bank Exams , CAT , GATE , GRE
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14 17741

Q:

A sum of money triples itself in 8 years simple interest. Find the rate of percent per annum?

A) 30%	B) 25%
C) 22%	D) 18%

Answer & Explanation Answer: B) 25%

Explanation:

The rate of percent R is given by,

exp.

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Filed Under: Simple Interest
Exam Prep: AIEEE , Bank Exams , CAT
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47 17740

Q:

The true discount on Rs. 2562 due 4 months hence is Rs. 122. The rate percent is?

A) 12%	B) 13%
C) 15%	D) 14%

Answer & Explanation Answer: C) 15%

Explanation:

P.W = 2562-122 =Rs.2440

Rate = [100 x 122] / [2440 x (1/3)] =15%

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Filed Under: True Discount

16 17736

Q:

Raju got married 8years ago. His present age is 6/5 times his age at the time of his marriage Raju's sister was 10years younger to him at the time of his marriage. The present age of Raju's sister is ?

A) 30	B) 32
C) 38	D) None

Answer & Explanation Answer: C) 38

Explanation:

Let Raju's age at the time of his marriage = X years

Then from given data

=> X + 8 = 6/5 X

X = 40.

Since got married 8 years ago, his present age = 48

His sister is 10 years younger => 48 - 10 = 38 years.

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Filed Under: Problems on Ages
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24 17735

Q:

A sum of money invested at compound interest amounts to Rs. 800 in 3 years and to Rs. 840 in 4 years. The rate of interest per annum is

A) 6%	B) 4%
C) 5%	D) 7%

Answer & Explanation Answer: C) 5%

Explanation:

S.I. on Rs.800 for 1 year

=Rs[840 - 800]

= Rs.40

Rate

=(100x40/800x1)%

= 5%

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Filed Under: Compound Interest
Exam Prep: Bank Exams
Job Role: Bank PO

15 17734

Q:

A hollow iron pipe is 21 cm long and its external diameter is 8 cm. If the thickness of the pipe is 1 cm and iron weighs 8g/cu.cm, then the weight of the pipe is

A) 3.6 kg	B) 3.696 kg
C) 36 kg	D) 36.9 kg

Answer & Explanation Answer: B) 3.696 kg

Explanation:

External radius = 4 cm

Internal radius = 3 cm

Volume of iron = $[\frac{22}{7} \times (4^{2} - 3^{2}) \times 21] c m^{3}$ = $462 c m^{3}$

Weight of iron = (462 x 8)gm = 3696 gm = 3.696 kg

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Filed Under: Volume and Surface Area

28 17728

Q:

In a class of 39 students the ratio of boys and girls is 2 : 1. Radhika ranks 15th among all the students from top and 8th among girls from bottom. How many boys are there below Radhika ?

A) 9	B) 17
C) 11	D) 15

Answer & Explanation Answer: B) 17

Explanation:

Total student= 39, boys : girls = 2:1, hence no of boys= 2/3(39)= 26
num of girls= 1/3(39) = 13 , since radhika ranked 15 among 39 student from top
and ranked 8 among girls from bottom , this means 7 girls are below radhika, rest 13-9= 5 girls are above her, now from 14 toper 5 are girls hence 14-5=9 boys.
Hence num of boys below radhika are 26-9=17

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Filed Under: Ratios and Proportions
Exam Prep: AIEEE , Bank Exams , CAT
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36 17719

Quantitative Aptitude - Arithmetic Ability Questions

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