WAEC Mathematics Past Questions & Answers - Page 201

1,001.

Given that \(p = x-\frac{1}{x} and\hspace{1mm}q = x^2 + \frac{1}{x^2}\) express q in terms of p.

A.

(p2 + 2)

B.

(p - 2) 2

C.

(p + 2) 2

D.

(p2 - 2)

Correct answer is A

Given \(p = x - \frac{1}{x}\); \(q = x^2 + \frac{1}{x^2}\).

\(p^2 = (x - \frac{1}{x})(x - \frac{1}{x})\)

\(p^2 = x^2 + \frac{1}{x^2} - 2\)

\(p^2 = q - 2 \implies q = p^2 + 2\)

1,002.

In the diagram O is the center of the circle, ∠SOR = 64° and ∠PSO = 36°. Calculate ∠PQR

A.

100o

B.

96o

C.

94o

D.

86o

Correct answer is D

< OSR = < ORS = \(\frac{180° - 64°}{2}\) = 58°

< PSR = 36° + 58° = 94°

< PSR + < PQR = 180°

94° + < PQR = 180° \(\implies\) < PQR = 180° - 94° = 86°

1,003.

In the diagram, \(QR||TP and W\hat{P}T = 88^{\circ} \). Find the value of x

A.

92o

B.

68o

C.

67o

D.

23o

Correct answer is C

Sum of the angles in a triangle = 180°

3x - 180° + 92° + x = 180°

4x - 88° = 180°

4x = 268°

x = 67°

1,004.

To arrive on schedule, a train is to cover a distance of 60km at 72km/hr. If it starts 10 minutes late, at what speed must it move to arrive on schedule?

A.

60km/hr

B.

80km/hr

C.

90km/hr

D.

108km/hr

Correct answer is C

\(speed = \frac{distance}{time}\\
72 = \frac{60}{time}\\
t = \frac{60}{72} = \frac{5}{6}hr\)
time lost = 10mis \(= \frac{10}{60}hr = \frac{1}{6}\)
Time required for the journey
\(=\frac{5}{6}-\frac{1}{6} = \frac{2}{3}\\
speed \hspace{1mm}=60 \div \frac{2}{3} = 90km/hr\)

1,005.

Calculate and correct to two significant figures, the percentage error in approximating 0.375 to 0.4

A.

2.0

B.

2.5

C.

6.6

D.

6.7

Correct answer is D

Measured value = 0.375
Approximation = 0.4
Error = 0.4 - 0.375 = 0.025
Error% = \(\frac{0.025}{0.375}\) x 100% = 6.67% = 6.7%