2008 - JAMB Mathematics Past Questions and Answers - page 5

X = ²⁰/₄

= 5

mean deviation = ⁸/₄ = 2

ACCEPTANCE = 10 Letters

A = 2 letters

C = 3 letters

E = 2 letters

Can be arranged in 10! / (2!3!2!) ways

(^{10}C_6 = \frac{10!}{(10-6)!6!}\

=\frac{10!}{4!6!}\

=\frac{10\times 9\times 8 \times 7 \times 6!}{4\times 3\times 2\times 1 \times 6!}\

=210)

OBSTRUCTION

Total possible outcome = 11

Number of chance of getting T = 2

P(picking T) = ²/₁₁

Total possible outcome

12+18+x+30+2x+45 = 105+3x

∴105+3x = 150

3x = 150-105

3x = 45

x = 15

P(obtaining 5) = (\frac{2x}{(105+3x)}But x= 15\

=\frac{2(15)}{(105+3(15))}\

=\frac{30}{(105+45)}\

=\frac{30}{150}\

=\frac{1}{5})

If 125_x = 20₁₀, find x

125_x = 1 x 3² + 2 x 3¹ + 5 x 3⁰

= 1 x 9 + 2 x 3 + 5 x 1

= 9 + 6 + 5

= 20

therefore, 125₃ = 20₁₀

x = 3

(\frac{\frac{3}{8} \div \frac {1}{2} - \frac{1}{3}}{\frac{1}{8} \times \frac {2}{3} + \frac{1}{3}})

= (\frac{\frac{3}{8} \times \frac {2}{1} - \frac{1}{3}}{\frac{1}{8} \times \frac {2}{3} + \frac{1}{3}})

= (\frac{\frac{6}{8} - \frac{1}{3}}{\frac{2}{24} + \frac{1}{3}})

= (\frac{\frac {18 - 8}{24}}{\frac{2 + 8}{24}}) = (\frac{\frac{10}{24}}{\frac{10}{24}})

= (\frac{10}{24}) (\div) (\frac{10}{24})

= (\frac{10}{24}) x (\frac{24}{10}) = 1

Express 123456 to 3 significant figures

= 123 000

Calculate the simple interest on N7500 for 8 years at 5% per annum

S.I = (\frac{P \times R \times T}{100})

S.I = (\frac{7500 \times 5 \times 8}{100})

S.I = (\frac{300000}{100})

S.I = N3000