WAEC Past Questions and Answers - Page 2384

11,916.

Find the quadratic equation whose roots are \(\frac{1}{2}\)  and -\(\frac{1}{3}\) 

A.

3x\(^2\) + x + 1 = 0

B.

6x\(^2\) + x - 1 = 0

C.

3x\(^2\) + x - 1 = 0

D.

6x\(^2\) - x - 1 = 0

Correct answer is D

x = \(\frac{1}{2}\) and x = \(\frac{-1}{3}\) 

(2x - 1) = 0 and (3x + 1) = 0

(2x - 1) (3x + 1) = 0

6x\(^2\) - x - 1 = 0

11,917.

Make m the subject of the relation k = \(\frac{m - y}{m + 1}\)

A.

m = \(\frac{y + k^2}{k^2 + 1}\)

B.

m = \(\frac{y + k^2}{1 - k^2}\)

C.

m = \(\frac{y - k^2}{k^2 + 1}\)

D.

m = \(\frac{y - k^2}{1 - k^2}\)

Correct answer is B

k = \(\frac{m - y}{m + 1}\)

k\(^2\) = \(\frac{m  - y}{m + 1}\)

k\(^2\)m + k\(^2\) = m - y 

k\(^2\) + y = m - k\(^2\)m

\(\frac{k^2 + y}{1 - k^2}\) = m\(\frac{(1 - k^2)}{1 - k^2}\)

m = \(\frac{y + k^2}{1 - k^2}\)

11,918.

Solve \(\frac{1}{3}\)(5 - 3x) < \(\frac{2}{5}\)(3 - 7x)

A.

x > \(\frac{7}{22}\)

B.

x < \(\frac{7}{22}\)

C.

x > \(\frac{-7}{27}\)

D.

x < \(\frac{-7}{27}\)

Correct answer is D

\(\frac{1}{3}\)(5 - 3x) < \(\frac{2}{5}\)(3 - 7x)

5(5 - 3x) < 6(3 - 7x)

25 - 15x < 18 - 42x 

- 15x + 42x < 18 - 25

\(\frac{27x}{27}\) < \(\frac{-7}{27}\)

x < \(\frac{-7}{27}\)

11,919.

The first term of a geometric progression (G.P) is 3 and the 5th term is 48. Find the common ratio. 

A.

2

B.

4

C.

8

D.

16

Correct answer is A

T\(_5\) = ar\(^4\) 

\(\frac{48}{3} = \frac{3r^4}{3}\)

16 = r\(^4\) 

r = \(4\sqrt{16}\)

= 2

11,920.

~ y \(\to\) ~ x

A.

~ y \(\to\) ~ x

B.

y \(\to\) ~ x

C.

~ x \(\to\) ~ y

D.

y \(\to\) x

Correct answer is C

No explanation has been provided for this answer.