2010 WAEC Mathematics Past Questions & Answers - page 1

Correct Option: D

Solution 0.000215215 x 0.000028

= 215 x 10^-4 x 28 x 10^-4

= 215 x 28 x 10^-6-6

= 6020 x 10^-12

= 6.020 x 10³ x 10^-12

= 6.02 x 10^{3 - 12}

= 6.02 x 10^-9

Correct Option: C

Solution x + y - ax = ay

= (x + y) -a(x + y) = (x + y)(1 - a)

Correct Option: D

Solution 1 litre = N63.00

xlitres = N900.00

x x N63 = N900 x 1 litre

x = \(\frac{900}{63} \times litre\)

x = \(\frac{100}{7}\) litres

Also, 1 litre = 14km

\(\frac{100}{7}\) = y

y x 1 litre = \(\frac{100litre}{7}\) x 14km

y = 20km

Correct Option: C

No further explanations yet...

Correct Option: D

Solution 1\(\frac{1}{2} + 2\frac{1}{3} \times \frac{3}{4} - \frac{1}{2}\)

\(\frac{3}{2} + \frac{7}{3} \times \frac{3}{4} - \frac{1}{2} = \frac{3}{2} + \frac{7}{4} - \frac{1}{2}\)

= \(\frac{6 + 7 - 2}{4} = \frac{11}{4}\)

= 2\(\frac{3}{4}\)

Correct Option: C

Solution Let the no. be x and x + 1

x + (x + 1) = \(\frac{5}{6}\) of x(x + 1)

2x + 1 = \(\frac{5}{6}\) x(x + 1)

6(2x + 1) = 5x² + 5x

12x + 6 = 5x² + 5x

5x² + 5x - 12x - 6 = 0

5x² - 7x - 6 = 0

5x² - 10x + 3x - 6 = 0

5x(x - 2) + 3(x - 2) = 0

(5x + 3)(x - 2) = 0

(5x + 3)(x - 2) = 0

(5x + 3) = 0

x - 2 = 0

for (5x + 3) = 0

5x = -3

x = \(\frac{-3}{5}\) (Imposible since x is a whole number)

x - 2 = 0

x = 2

x = \(\frac{-3}{5}\)(Impossible since x is a whole number)

x - 2 = 0

x = 2

The numbers are x = 2

x + 1 = 2 + 1

= 3

Correct Option: B

Solution %Zinc + %Copper = 100%

65% + %Copper = 100%

%Copper = 100% - 65% = 35%

%Copper = \(\frac{\text{Mass of % Copper}}{\text{Mass of Casting}}\) x 100%

Mass of Casting = \(\frac{147}{35}\) x 100%

= 420g

Correct Option: A

Solution P = {1, 2, 3, 4, 5, 6}; Q = {3, 4, 5, 6, 7, 8, 9}

P \(\cap\) Q) = {2, 4, 5, 6}

n(P \(\cap\) Q) = 4

Correct Option: C

Solution 6 = \(\frac{1}{3}x\) = 1 + 2x

6 = 1 = \(\frac{2x}{1} - \frac{x}{3}\)

5 = \(\frac{6x - x}{3} = \frac{5x}{3}\)

5 = \(\frac{5x}{3}\)

3 x 5 = 5x

15 = 5x

x = \(\frac{15}{5}\)

= 3

Correct Option: C

Solution T = {-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9}

n(T) = 11