2007 - WAEC Mathematics Past Questions and Answers - page 5

Sum = 8 + 6 + 7 + 2 + 0 + 4 + 7 + 2 + 3 = 39

mean = \(\frac{39}{9}\) = 4.33

then \(\frac{sum}{mean}\) = \(\frac{39}{4.33}\)

= 9

cos 40 = \(\frac{x}{200}\)

x - 200 x cosx

= 200 x 0.7660

x = 153.2m

Let normal working hour = x

let overtime = y

after 10 hours = N31.00

1 x 2.50x + 4y = 31

4 x x + y = 10

2.50x + 4y = 31
- 4x + 4y = 30
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-1.5x = -9

x = 6; x + y = 10

6 + y = 10

y = 10 - 4

y = 4hrs for over time

SI = \(\frac{PRT}{100}\)

39 = \(\frac{520 \times R \times 3}{100}\)

1560R = 3900

R = \(\frac{3900}{1560}\)

= 2.5%

R = 2\(\frac{1}{2}\)%

By Pythagoras theorem

h² = (2\(\sqrt{3})^2 - (\sqrt{3})^2\)

= 2²(\(\sqrt{3})^2 - 3\)

4(3) - 3 = 112 - 3

h² = 9

h = \(\sqrt{9}\)

= 3cm

2 - x - x²; (2 - 2x) + (x - x²)

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

= (1 - x)(2 + x)

= 1 - x

\(\frac{a + bc}{wd + f}\) = g(cross multiply)

a = bc + wdg + fg

wdg = a + bc - fg

w = \(\frac{a + bc - fg}{dg}\)

4x - 3(2x - 1) > 1

4x - 6x + 3 > 1

-2x > 1 - 3; 2x > -2

x < \(\frac{-2}{-2}\)

= x < 1