WAEC Past Questions and Answers - Page 4247

21,231.

A sales girl gave a change of N1.15 to a customer instead of N1.25. Calculate her percentage error

A.

10%

B.

7%

C.

8.0%

D.

2.4%

E.

10%

Correct answer is C

Error = 1.25 - 1.15 = 0.10

 

0.10/1.25

* 100 = 8.0%

21,232.

Find the quadratic equation whose roots are x = -2 or x = 7

A.

x2 + 2x - 7 = 0

B.

x2 - 2x + 7 = 0

C.

x2 + 5 +14 = 0

D.

x2 - 5x - 14 = 0

E.

x2 + 5x - 14 = 0

Correct answer is D

x + 2 and x - 7 are factors
(x+2)(x+7) = 0

x(x-7) + 2(x-7) = 0

x2 - 7x + 2x - 14 = 0

x2 - 5x - 14 = 0

21,233.

A student told to draw the graph of y = x2 + 4x - 6. He is then told to draw a liner graph on the same axis such that the intersection of the two graphs will give the solutions to the equation x2 + 4x - 7 = 0, What is the equation of the linear graph he needs to draw?

A.

x = 1

B.

x = -1

C.

y = 1

D.

y = -1

E.

x + y = 1

Correct answer is C

The linear equation will be the difference between the equation.

y=x2 + 4x - 6 and x2 + 4x - 7 = 0

y=x2 + 4x - 6, ( 0 = x2 + 4x - 7)

y = -(-1) y = 1

21,234.

If sinθ = 3/5 find tanθ for 0 < θ < 90o

A.

4\5

B.

3\4

C.

5\8

D.

1\2

E.

3\8

Correct answer is B

sinθ = 3/5
tanθ = 3/4

21,235.

Points P and Q respectively 24m north and 7m east point R. What is the bearing of Q from P to the nearest whole degree?

A.

16o

B.

17o

C.

73o

D.

106o

E.

164o

Correct answer is E

Using pythagoras' theorem:

Hyp\(^2\) = Adj\(^2\) + Opp\(^2\) → 24\(^2\) + 7\(^2\)

Hyp = √625 → 25

\(\tan P = \frac{7}{24}\)

\(\tan P = 0.2917\)

\(P = \tan^{-1} (0.2917)\)

= 16.26° 

Bearing of Q from P = 180° - 16.26°

= 163.74° \(\approxeq\) 164°