List of top General Aptitude Questions on Number Systems

The product of the digits of a three-digit number is 70. The sum of the digits of the three-digit number is:

If \( P e^x = Q e^{-x} \) for all real values of \( x \), which one of the following statements is true?

Let \( P(x) \) be an arbitrary predicate over the domain of natural numbers. Which ONE of the following statements is TRUE?

Consider a five-digit number \(PQRST\) that has distinct digits \(P, Q, R, S,\) and \(T\), and satisfies the following conditions: \[ P<Q, S>P>T, R<T \] If integers 1 through 5 are used to construct such a number, the value of \(P\) is:

Let $p_1$ and $p_2$ denote two arbitrary prime numbers. Which one of the following statements is correct for \emph{all values of $p_1$ and $p_2$?}

The sum of the digits of a two-digit number is 10. If 18 is subtracted from it, the digits in the resulting number will be equal. The number is:

A 6-digit number has digits as consecutive natural numbers. The number is always divisible by:

If the mean of 3, 4, 9, 2k, 10, 8, 6 and $(k + 6)$ is 8, and the mode of 2, 2, 3, $2p$, $(2p + 1)$, 4, 4, 5 and 6 (where $p$ is a natural number) is 4, then the value of $k - 2p$ is:

In the Delhi zoo, there are some ducks and rabbits. If the heads are counted there are 160, while the legs are 450. What will be the number of ducks in the zoo?

The difference of the greatest and the smallest of the fractions $\frac{1}{2}$, $\frac{8}{11}$, $\frac{7}{8}$, $\frac{7}{9}$, $\frac{5}{6}$ is:

Which one of the given options is a possible value of $x$ in the following sequence? \[ 3,\; 7,\; 15,\; x,\; 63,\; 127,\; 255 \]

For positive non-zero real variables \( x \) and \( y \), if \[ \ln \left( \frac{x + y}{2} \right) = \frac{1}{2} \left[ \ln(x) + \ln(y) \right], \] then, the value of \( \frac{x}{y} + \frac{y}{x} \) is:

In an engineering college of 10,000 students, 1,500 like neither their core branches nor other branches. The number of students who like their core branches is \( \frac{1}{4} \) of the number of students who like other branches. The number of students who like both their core and other branches is 500. The number of students who like their core branches is:

The information contained in DNA is used to synthesize proteins necessary for life. DNA is composed of four nucleotides: Adenine (A), Thymine (T), Cytosine (C), and Guanine (G). Coding regions—where nucleotide triplets code for amino acids—constitute only about 2% of human DNA. Based only on the information above, which of the following statements can be inferred with {certainty}? (i) The majority of human DNA has no role in the synthesis of proteins. (ii) The function of about 98% of human DNA is not understood.

The average of the monthly salaries of M, N and S is ₹4000. The average of the monthly salaries of N, S and P is ₹5000. The monthly salary of P is ₹6000.
What is the monthly salary of M as a percentage of the monthly salary of P?

A person travelled 80 km in 6 hours. If the person travelled the first part with a uniform speed of 10 kmph and the remaining part with a uniform speed of 18 kmph. What percentage of the total distance is travelled at a uniform speed of 10 kmph?

Three bells P, Q, and R are rung periodically in a school. P is rung every 20 minutes; Q is rung every 30 minutes and R is rung every 50 minutes.
If all the three bells are rung at 12:00 PM, when will the three bells ring together again the next time?

p and q are positive integers and \[ \frac{p}{q} + \frac{q}{p} = 3, \] then, \[ \frac{p^2}{q^2} + \frac{q^2}{p^2} = \]