JAMB Mathematics Past Questions & Answers - Page 253

2log $\frac{2}{5}$ - log$\frac{72}{125}$ + log 9

[$\frac{2}{5}$)² x 9] = log $\frac{4}{25}$ x $\frac{9}{1}$ x $\frac{125}{72}$

= log $\frac{72}{125}$

= log $\frac{5}{2}$

= log $\frac{10}{4}$

= log 10 - log 4

= log₁₀ 10 - log₁₀ 22

= 1 - 2 log2

$\frac{27}{5^1}$(3)-3 x $\frac{(1)^{-1}}{5}$ = $\frac{27}{5}$ x $\frac{1}{3^3}$ x $\frac{1}{\frac{1}{5}}$

= $\frac{27}{5}$ x $\frac{1}{27}$ x $\frac{1}{5}$

=  $\frac{1}{25}$

% of water in the mixture

= $\frac{\text{Total Amount of water}}{\text{Total quantity of spirit}}$ x $\frac{100}{1}$

$\frac{3(\frac{20}{100}) + 5 (\frac{15}{100})}{3 + 5}$ x $\frac{100}{1}$

= $\frac{\frac{6}{10} + \frac{75}{100}}{8}$ x $\frac{100}{1}$

= $\frac{0.6 + 0.75}{8}$ x $\frac{100}{1}$


= $\frac{1.35}{8}$ x $\frac{100}{1}$

= $\frac{33.75}{2}$

= 16.875

= 16$\frac{7}{8}$

I = $\frac{PRT}{100}$

= $\frac{10 \times 2 \times 4}{100}$

= $\frac{4}{5}$

= 0.8

Total amount = N10.80

He pays N8.00

Remainder = 10.80 - 8.00

= N2.80

P produces 20,000 bags

P reduces production by 5%

i.e. reduction = $\frac{5}{100}$ x $\frac{20000}{1}$

= 1000

Q produces 15000 bags

Q increases production by 5%

i.e. increase = $\frac{5}{100}$ x $\frac{15000}{1}$

= 750

Effective loss by the two = 1000 - 750

= 250 bags