NECO Past Questions and Answers - Page 144

716.

If sin θ = \(\frac{\sqrt{3}}{2}\) and 0 < θ < 180°, what is cos θ ?

A.

\(\frac{1}{\sqrt{3}}\)

B.

\(\frac{2}{\sqrt{3}}\)

C.

\(\frac{1}{2}\)

D.

\(\frac{\sqrt{3}}{2}\)

E.

\(\sqrt{3}\)

Correct answer is C

No explanation has been provided for this answer.

717.

>What are the factors of 2x\(^2\) - xy - 3y\(^2\) ?

A.

(2x + 3y)(x + y)2

B.

(2x + 3y)(x + y)

C.

(2x + 3y)(x - y)

D.

(2x - 3y)(x + y)

E.

(2x - 3y)(x - y)

Correct answer is D

2x\(^2\) - xy - 3y\(^2\)

= 2x\(^2\) + 2xy - 3xy - 3y\(^2\)

= 2x(x + y) - 3y(x + y)

= (2x - 3y)(x + y)

718.

A quadratic equation with roots -1\(\frac{1}{2}\) and \(\frac{1}{4}\) is

A.

x2 + 3x + 4 = 0

B.

8x2 + 10x + 3 = 0

C.

8x2 +12x – 3 = 0

D.

8x2 + 10x-3.= 0

E.

8x2 + 12x + 3 = 0

Correct answer is D

No explanation has been provided for this answer.

719.

One bag contains 4 white balls and 2 black balls. Another bag contains 3 white balls and 5 black balls, if one ball is drawn from each bag, what is the probability that both are white?

A.

\(\frac{2}{3}\)

B.

\(\frac{3}{8}\)

C.

\(\frac{7}{24}\)

D.

\(\frac{1}{4}\)

E.

\(\frac{1}{24}\)

Correct answer is D

No explanation has been provided for this answer.

720.

A wire was shaped to form a square of area 81cm\(^2\). An equilateral triangle was formed by the same wire,What is the length of a side of the triangle formed?

A.

3cm

B.

6cm

C.

9cm

D.

12cm

E.

27cm

Correct answer is D

Area of a square = L X L = 81

: L = 9

Perimeter of square = 4 X L 

 4 X 9 = 36cm

An equilateral triangle with equal sides:

 36/3 = 12cm