WAEC Mathematics Past Questions & Answers - Page 33

161.

Simplify; \(\frac{a}{b} - \frac{b}{a} - \frac{c}{b}\)

A.

\(\frac{a - b + c}{ab}\)

B.

\(\frac{ab - bc - ac}{ab}\)

C.

\(\frac{a^2 - b^2 + ac}{ab}\)

D.

\(\frac{a^2 - b^2 - ac}{ab}\)

Correct answer is D

\(\frac{a}{b} - \frac{b}{a} - \frac{c}{b}\)

\(\frac{a^2 - b^2- ac}{ab}\) 

162.

A man is five times as old as his son. In four years' time, the product of their ages would be 340. If the son's age is y, express the product of their ages in terms of y.

A.

5y\(^2 - 16y - 380 = 0\)

B.

5y\(^2 - 24y - 380 = 0\)

C.

5y\(^2 - 16y - 330 = 0\)

D.

5y\(^2 + 24y - 324 = 0\)

Correct answer is D

Man = x, Son = y 

x = 5y

(x + 4)(y + 4) = 350

(5y + 4)(y + 4) = 340

5y\(^2\) + 20y + 4y + 16 - 240 = 0

5y\(^2\) + 24y - 324 = 0

163.

The expression \(\frac{5x + 3}{6x (x + 1)}\) will be undefined when x equals 

A.

{0, 1}

B.

{0, -1}

C.

{-3, -11}

D.

{-3, 0}

Correct answer is B

6x(x + 1) = 0

When 6x = 0 and 

x + 1 = 0

x = 0 and x = -1

(0, -1)

164.

Find the equation of the line parallel to 2y = 3(x - 2) and passes through the point (2, 3) 

A.

y = \(\frac{2}{3} x - 3\)

B.

y = \(\frac{2}{3} x - 2\)

C.

y = \(\frac{2}{3} x\)

D.

y = \(\frac{-2}{3} x\)

Correct answer is C

2y = 3(x - 2)

\(\frac{2y}{2} = \frac{3x}{2} - \frac{6}{2}\)

y = \(\frac{3}{2}x - 3\)

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

\(\frac{y - y_1}{x - x_1}\) = m

\(\frac{y - 3}{x - 2} = \frac{3}{2}\)

2y - 6 = 3x - 6

\(\frac{2y}{2} = \frac{3x}{2}\) 

y = \(\frac{3}{2}\)x

165.

In the diagram, PQ // SR. Find the value of x

A.

34

B.

46

C.

57

D.

68

Correct answer is B

x + 68\(^o\)  + 246\(^o\) = 360\(^o\)

x + 314\(^o\) = 360\(^o\)

x = 360\(^o\) - 314\(^o\)

x = 46\(^o\)