Quantitative Aptitude
Number System and Simplification
585 Questions
Number system and simplification questions assess mathematical proficiency in handling fractions, decimals, and complex algebraic expressions. Test takers must simplify surds, calculate reciprocals, and solve intricate number pattern equations. This foundational quantitative aptitude topic is critical for achieving high scores in SSC and banking exams.
Fraction simplificationDecimal operationsSurds and indicesPercentage calculationsComplex number algebra
Number System and Simplification Questions
Use the Möbius Inversion Formula to find a formula for the sum of the divisors of an integer ( n ).
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\( \sum_{d|n} d = n \)
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\( \sum_{d|n} d = \phi(n) \)
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\( \sum_{d|n} d = \sigma(n) \)
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\( \sum_{d|n} d = \mu(n) \)
C
Correct answer
Explanation
Using the Möbius Inversion Formula with ( f(n) = d ) and ( g(n) = \sum_{d|n} \mu(d) d ), we get ( d = \sum_{d|n} \mu(d) g(\frac{n}{d}) ). Since ( g(\frac{n}{d}) = \sigma(\frac{n}{d}) ) for all ( d | n ), we have ( \sum_{d|n} d = \sigma(n) ).
Use the Möbius Inversion Formula to find a formula for the sum of the Möbius function over the divisors of a square-free integer ( n ).
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\( \sum_{d|n} \mu(d) = 1 \)
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\( \sum_{d|n} \mu(d) = n \)
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\( \sum_{d|n} \mu(d) = \phi(n) \)
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\( \sum_{d|n} \mu(d) = \sigma(n) \)
A
Correct answer
Explanation
Since ( n ) is square-free, all of its divisors are also square-free. Therefore, ( \mu(d) = 1 ) for all ( d | n ). Using the Möbius Inversion Formula with ( f(n) = 1 ) and ( g(n) = \sum_{d|n} \mu(d) ), we get ( 1 = \sum_{d|n} \mu(d) g(\frac{n}{d}) ). Since ( g(\frac{n}{d}) = 1 ) for all ( d | n ), we have ( \sum_{d|n} \mu(d) = 1 ).
Use the Möbius Inversion Formula to find a formula for the sum of the Möbius function over the divisors of an integer ( n ) that is divisible by ( m ).
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\( \sum_{d|n} \mu(d) = 1 \)
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\( \sum_{d|n} \mu(d) = n \)
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\( \sum_{d|n} \mu(d) = \phi(n) \)
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\( \sum_{d|n} \mu(d) = \sigma(n) \)
Correct answer
Explanation
If ( m ) is divisible by ( n ), then all of the divisors of ( n ) that are divisible by ( m ) are also divisible by ( \frac{n}{m} ). Therefore, ( \mu(d) = 0 ) for all ( d | n ) that are divisible by ( m ). Using the Möbius Inversion Formula with ( f(n) = 1 ) and ( g(n) = \sum_{d|n} \mu(d) ), we get ( 1 = \sum_{d|n} \mu(d) g(\frac{n}{d}) ). Since ( g(\frac{n}{d}) = 0 ) for all ( d | n ) that are divisible by ( m ), we have ( \sum_{d|n} \mu(d) = \begin{cases} 1 & \text{if } m = 1 \ 0 & \text{if } m > 1 \end{cases} ).
Use the Möbius Inversion Formula to find a formula for the sum of the Möbius function over the divisors of an integer ( n ) that is not divisible by ( m ).
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\( \sum_{d|n} \mu(d) = 1 \)
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\( \sum_{d|n} \mu(d) = n \)
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\( \sum_{d|n} \mu(d) = \phi(n) \)
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\( \sum_{d|n} \mu(d) = \sigma(n) \)
Correct answer
Explanation
If ( m ) is not divisible by ( n ), then there is at least one prime factor of ( n ) that is not a prime factor of ( m ). Therefore, there is at least one divisor of ( n ) that is not divisible by ( m ). Since ( \mu(d) = 0 ) for all ( d | n ) that are divisible by ( m ), we have ( \sum_{d|n} \mu(d) = -1 ). Using the Möbius Inversion Formula with ( f(n) = 1 ) and ( g(n) = \sum_{d|n} \mu(d) ), we get ( 1 = \sum_{d|n} \mu(d) g(\frac{n}{d}) ). Since ( g(\frac{n}{d}) = -1 ) for all ( d | n ) that are not divisible by ( m ), we have ( \sum_{d|n} \mu(d) = \begin{cases} 0 & \text{if } m = 1 \ -1 & \text{if } m > 1 \end{cases} ).
Use the Möbius Inversion Formula to find a formula for the sum of the Möbius function over the divisors of an integer ( n ) that are not relatively prime to ( n ).
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\( \sum_{d|n} \mu(d) = 1 \)
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\( \sum_{d|n} \mu(d) = n \)
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\( \sum_{d|n} \mu(d) = \phi(n) \)
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\( \sum_{d|n} \mu(d) = \sigma(n) \)
Correct answer
Explanation
If ( d ) is a divisor of ( n ) that is not relatively prime to ( n ), then there is at least one prime factor of ( n ) that is also a prime factor of ( d ). Therefore, ( \mu(d) = 0 ). Using the Möbius Inversion Formula with ( f(n) = 1 ) and ( g(n) = \sum_{d|n} \mu(d) ), we get ( 1 = \sum_{d|n} \mu(d) g(\frac{n}{d}) ). Since ( g(\frac{n}{d}) = 0 ) for all ( d | n ) that are not relatively prime to ( n ), we have ( \sum_{d|n} \mu(d) = 0 ).
What is the Brahmagupta formula?
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$x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$
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$x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$
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$x = \frac{-b \pm \sqrt{b^2 + 4ac}}{2a}$
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$x = \frac{-b \pm \sqrt{b^2 - 4ac}}{4a}$
A,B
Correct answer
Explanation
The Brahmagupta formula is given by the equation $x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a}$, where $a$, $b$, and $c$ are the coefficients of the quadratic equation $ax^2 + bx + c = 0$.
What is the general formula for the Madhava series for the arctangent function?
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$$\arctan x = x - \frac{x^3}{3} + \frac{x^5}{5} - \frac{x^7}{7} + \cdots$$
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$$\arctan x = x - \frac{x^3}{3!} + \frac{x^5}{5!} - \frac{x^7}{7!} + \cdots$$
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$$\arctan x = x - \frac{x^3}{3} + \frac{x^5}{5} - \frac{x^7}{7} + \cdots$$
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$$\arctan x = x - \frac{x^3}{3!} + \frac{x^5}{5!} - \frac{x^7}{7!} + \cdots$$
A,C
Correct answer
Explanation
The general formula for the Madhava series for the arctangent function is $$\arctan x = x - \frac{x^3}{3} + \frac{x^5}{5} - \frac{x^7}{7} + \cdots$$.
What is the general formula for the Madhava series for pi?
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$$\pi = 4 \left(1 - \frac{1}{3} + \frac{1}{5} - \frac{1}{7} + \cdots\right)$$
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$$\pi = 4 \left(1 - \frac{1}{3} + \frac{1}{5} - \frac{1}{7} + \cdots\right)$$
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$$\pi = 4 \left(1 - \frac{1}{3} + \frac{1}{5} - \frac{1}{7} + \cdots\right)$$
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$$\pi = 4 \left(1 - \frac{1}{3} + \frac{1}{5} - \frac{1}{7} + \cdots\right)$$
A,B,C,D
Correct answer
Explanation
The general formula for the Madhava series for pi is $$\pi = 4 \left(1 - \frac{1}{3} + \frac{1}{5} - \frac{1}{7} + \cdots\right)$$.
What is the value of the following expression: (\frac{1}{2} + \frac{1}{3} + \frac{1}{6})?
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\(\frac{11}{6}\)
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\(\frac{5}{6}\)
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\(\frac{7}{6}\)
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\(\frac{9}{6}\)
A
Correct answer
Explanation
To find the value of the expression, we can add the fractions as follows: (\frac{1}{2} + \frac{1}{3} + \frac{1}{6} = \frac{3}{6} + \frac{2}{6} + \frac{1}{6} = \frac{6}{6} = \frac{11}{6}).
What is the general formula for the Madhava series for the arctangent function?
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$$arctan(x) = x - \frac{x^3}{3} + \frac{x^5}{5} - \frac{x^7}{7} + \cdots$$
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$$arctan(x) = x + \frac{x^3}{3} + \frac{x^5}{5} + \frac{x^7}{7} + \cdots$$
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$$arctan(x) = x - \frac{x^3}{3} - \frac{x^5}{5} - \frac{x^7}{7} + \cdots$$
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$$arctan(x) = x + \frac{x^3}{3} - \frac{x^5}{5} - \frac{x^7}{7} + \cdots$$
A
Correct answer
Explanation
The general formula for the Madhava series for the arctangent function is $$arctan(x) = x - \frac{x^3}{3} + \frac{x^5}{5} - \frac{x^7}{7} + \cdots$$. This series converges for all values of x between -1 and 1.
What is the general formula for the Madhava series for pi?
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$$\pi = 4 \left(1 - \frac{1}{3} + \frac{1}{5} - \frac{1}{7} + \cdots\right)$$
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$$\pi = 4 \left(1 + \frac{1}{3} + \frac{1}{5} + \frac{1}{7} + \cdots\right)$$
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$$\pi = 4 \left(1 - \frac{1}{3} - \frac{1}{5} - \frac{1}{7} + \cdots\right)$$
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$$\pi = 4 \left(1 + \frac{1}{3} - \frac{1}{5} - \frac{1}{7} + \cdots\right)$$
A
Correct answer
Explanation
The general formula for the Madhava series for pi is $$\pi = 4 \left(1 - \frac{1}{3} + \frac{1}{5} - \frac{1}{7} + \cdots\right)$$. This series converges very slowly, but it was the first series expansion for pi to be discovered.
The equation (\frac{a}{b} = \frac{c}{d}) is known as:
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Pythagorean theorem
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Euler's formula
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Cross-multiplication rule
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Law of sines
C
Correct answer
Explanation
The equation (\frac{a}{b} = \frac{c}{d}) is known as the cross-multiplication rule, which is used to solve proportions.
In modular arithmetic, what is the value of 7^3 mod 5?
C
Correct answer
Explanation
Modular arithmetic involves calculations with integers modulo a fixed integer. In this case, we are working modulo 5. To find 7^3 mod 5, we can calculate 7^3 = 343, and then divide it by 5 to get the remainder. 343 ÷ 5 = 68 remainder 3. Therefore, 7^3 mod 5 = 3.
What is the value of the Gamma function at (\frac{1}{2})?
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$\sqrt{\pi}$
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$\frac{1}{\sqrt{\pi}}$
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$\frac{\pi}{2}$
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$\frac{2}{\pi}$
A
Correct answer
Explanation
The Gamma function at (\frac{1}{2}) is equal to (\sqrt{\pi}).
What is the value of the Gamma function at (\frac{3}{2})?
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$\frac{\sqrt{\pi}}{2}$
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$\frac{2}{\sqrt{\pi}}$
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$\frac{\pi}{2}$
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$\frac{3\sqrt{\pi}}{2}$
A
Correct answer
Explanation
The Gamma function at (\frac{3}{2}) is equal to (\frac{\sqrt{\pi}}{2}).