2006 - WAEC Mathematics Past Questions and Answers - page 2

ratio of boys to girls = 5:3

total = 5 + 3 = 8

Pr(girl) = (\frac{3}{8})

y = k(\sqrt{x}) when y = 1, x = 4

k = (\frac{y}{\sqrt{x}})

= (\frac{1}{\sqrt{4}})

= (\frac{1}{2})

= 0.5

From y = (\frac{1}{2} \sqrt{x})

when y = 2.5 or (\frac{5}{2}), x = P

(\frac{5}{2} \times \frac{1}{2} \sqrt{P})

(\sqrt{P} = \frac{10}{2} = 5)

P = 5²

= 25

x² - 3x + k(perfect square)

k = (-(\frac{3}{2}))2 ; k = (\frac{9}{4})

(2x - 1)(x + 5) = 2x² - mx - 5

2x² + 10x - x - 5

= 2x² + 9x - 5 = 2x² - mx - 5

comparing the co-efficient of x

-m = 9

m = -9

Place value of 9 in 3.0492

= 0.009

= (\frac{9}{1000})

I = N123; R = 3%' T = 2(\frac{1}{2}) yrs; P = (\frac{100 \times 1}{RT})

P = (\frac{100 \times 123}{3 \times 2.5})

principal(P) = N1640

D = P(I - (\frac{R}{100}))ⁿ where P = N20,000; R = 10%, n = 2

D = 20,000(I - (\frac{10}{100}))²

= 20000(0.9)²

20,000 x 0.81 = N16,200

The value for which the equation is impossible

2x = 10 (if y = 0)

x = 5

x + y = 12

• 3x - y = 20
  ---------------
  4x = 32
  
  

x = 8

x + y = 12; 8 + y = 12; y = 12 - 8

= 4

2x - y = 2(8) - 4; 16 - 4 = 12