# ECAT – Mathematics (Numbers Systems)

The following questions are from the basics of numbers systems, rational and irrational numbers, complex numbers and their properties.

**Mathematics-Number Systems Sample Questions**

1. If a = b and b = c, then a = c. This property is called ?

(A) Reflexive

(B) Transitive

(C) Trichotomy

(D) Symmetric

2. If a > b and b > a, then ?

(A) a = b

(B) a ≠ b

(C) cannot be evaluated

(D) impossible

3. π (pi) denotes the ratio of the __________ to the __________ .

(A) area of a circle, circumference of the circle

(B) area of a circle, length of its diameter

(C) circumference of a circle, length of its radius

(D) circumference of a circle, length of its diameter

4. The value of π (pi) is a/an __________ .

(A) rational number

(B) irrational number

(C) integer

(D) complex number

5. If x^{2} + 1 = 0, then x = ?

(A) 1

(B) *i*

(C) ± 1

(D) ± *i*

**Answers**

**1. B**

**2. A**

**3. D**

**4. B**

**5. D**

6. The product of complex numbers (4,3) and (5,−6) is ?

(A) (18,3)

(B) (18,−3)

(C) (38,9)

(D) (38,−9)

7. (2,6) ÷ (4,2) = ?

(A) (1,1)

(B) (1,2)

(C) (2,1)

(D) (2,2)

8. (−*i*)^{−19} = ?

(A) 1

(B) −1

(C) *i*

(D) −*i*

9. The multiplicative identity of a complex number is ?

(A) (0,0)

(B) (1,0)

(C) (0,1)

(D) (1,1)

10.

(A) 9

(B) −9

(C) 9*i*

(D) −9*i*

**Answers**

**6. D**

**7. A**

**8. D**

**9. B**

**10. B**