Practice MCQ Questions and Answer on Number System
1.
The sum and products of two numbers are 12 and 35 respectively. The sum of their reciprocals will be:
- (A) $$\frac{1}{3}$$
- (B) $$\frac{1}{5}$$
- (C) $$\frac{{12}}{{35}}$$
- (D) $$\frac{{35}}{{12}}$$
2.
Find the product of all odd natural numbers less than 5000.
- (A) $$\frac{{5000!}}{{{2500} \times 2501}}$$
- (B) $$\frac{{5000!}}{{{2^{2500}} \times 2500!}}$$
- (C) $$\frac{{5000!}}{{{2^{5000}}}}$$
- (D) None of these
3.
What is least possible number when it is divided by 13 leaves 8 and when divided by 7 leaves remainder 6?
- (A) 48
- (B) 34
- (C) 40
- (D) 41
4.
$$\frac{1}{{10}}$$ of a rod is coloured red, $$\frac{1}{{20}}$$ orange, $$\frac{1}{{30}}$$ yellow, $$\frac{1}{{40}}$$ green, $$\frac{1}{{50}}$$ blue, $$\frac{1}{{60}}$$ black and the rest is violet. If the length of the violet part of the rod is 12.08 mtr, then the length of the rod is -
- (A) 16 m
- (B) 18 m
- (C) 20 m
- (D) 30 m
5.
Let n be a natural number such that $$\frac{1}{2}$$ + $$\frac{1}{3}$$ + $$\frac{1}{7}$$ + $$\frac{1}{n}$$ ÃÂÃÂ is also a natural number. Which of the following statements is not true ?
- (A) 2 divides n
- (B) 3 divides n
- (C) 7 divides n
- (D) n > 84
6.
Which one of the following numbers is divisible by 3 ?
- (A) 4006020
- (B) 2345678
- (C) 2876423
- (D) 9566003
7.
If the number 357*25* is divisible by both 3 and 5, then the missing digits in the unit's place and the thousandth's place respectively are :
- (A) 0, 6
- (B) 5, 1
- (C) 5, 4
- (D) None of these
8.
6 ÃÂÃÂÃÂÃÂÃÂÃÂ 3 (3 - 1) is equal to :
- (A) 19
- (B) 20
- (C) 36
- (D) 53
9.
The unit's digit of 132003 is :
- (A) 1
- (B) 3
- (C) 7
- (D) 9
10.
The sum of four consecutive two-digit odd numbers, when divided by 10, become a perfect square. Which of the following can possibly be one of these four numbers?
- (A) 21
- (B) 25
- (C) 41
- (D) 67