Practice Basic number system - quantitative aptitude Online Quiz (set-1) For All Competitive Exams
Q-1) There are just two ways in which 5 may be expressed as the sum of two different positive (non-zero) integers, namely 5 = 4 + 1 = 3 + 2. In how many ways, 9 can be expressed as the sum of two different positive (non-zero) integers?
(a)
(b)
(c)
(d)
9 = 1+8 = 2+7 = 3+6 = 4+5
So it can be expressed in 4 ways
Q-2) P and Q are two positive integers such that PQ = 64. Which of the following cannot be the value of P + Q?
(a)
(b)
(c)
(d)
The possible combinations of (P, Q)
So that the product is 64 are
(1, 64), (2, 32), (4, 16) and (8, 8)
∴ P+Q cannot be 35
Q-3) If n is an integer between 20 and 80, then any of the following could be n+7 except
(a)
(b)
(c)
(d)
Given, 20 < n < 80
Now n + 7 = ?
20 + 7 < n + 7 < 80 + 7
i.e., 27 < n + 7 < 87
∴ 88 does not lies between 27 to 87.
Q-4) If x, y, z be the digits of a number beginning from the left, the number is
(a)
(b)
(c)
(d)
In this problem, the digits of the number from the left are x, y and z respectively.
So, x is at hundreds places, y is at tens place and z is at ones place.
Thus, the required number be
= (100×x) + (10×y) + (1×z)
= (100x + 10y + z)
Q-5) Consider the following statements about natural numbers: (1) There exists a smallest natural number. (2) There exists a largest natural number. (3) Between two natural numbers, there is always a natural number. Which of the above statements is/are correct?
(a)
(b)
(c)
(d)
1) There exists the smallest natural number - which is 1. So, true.
2) There exists a largest natural number - there is no upper limit to numbers. So, false.
3) Between two natural numbers there is always a natural number - for example, between 1 and 2 there is no natural number. So, false.
Hence, only option 1 is true.
Q-6) If x, y, z and w be the digits of a number beginning from the left, the number is
(a)
(b)
(c)
(d)
In this problem, the digits of the number from the left are x, y, z and w respectively.
So, x is at thousands places, y is at hundreds of places, z is at tens place and w is at ones place.
Thus, the required number be
= (1000×x) + (100×y) + (10×z) + (1×w)
= (1000x + 100y + 10z + w)
Q-7) If n and p are both odd numbers, which of the following is an even number?
(a)
(b)
(c)
(d)
Let for example:
n=3 p=5
Option a) 3 + 5 = 8 (even number)
Option b) 3 + 5 + 1 = 9 (odd number)
Option c) 3 x 5 + 2 = 17 (odd number)
Option d) 3 x 5 = 3 (odd number)
Q-8) For the integer n, if $n^3$ is odd, then which of the following statements are true? I. n is odd. II. $n^2$ is odd. III. $n^2$ is even
(a)
(b)
(c)
(d)
If n3 is odd
⇒ n is odd and n2 is odd
For example
$n^3$ = 27. Then n = 3 & $n^2$ = 9
∴ I and II are true.
Q-9) If (n - 1) is an odd number, what are the two other odd numbers nearest to it?
(a)
(b)
(c)
(d)
(n – 1) is odd
⇒ (n – 1) – 2 & (n – 1) + 2 are odd.
⇒ (n – 3) and (n + 1) are odd.
Q-10) All natural numbers and 0 are called as _______ numbers.
(a)
(b)
(c)
(d)
The counting numbers {1, 2, 3, ...} are commonly called natural numbers; however, include 0, so that the non-negative integers {0, 1, 2, 3, ...} are also called natural numbers.
Natural numbers including 0 are also called whole numbers.
Also, Refer to Types of Numbers.