BECE Mathematics 2020 Paper

Let $x$ be the cost of one book$\;12 \;\text{ books}\;=54.84$$\;1 \;\text{ book}\;=x$Cross multiplying the equations$\Rightarrow 12 \times x = 1 \times 54.84$Divide both sides by 12$\;\Rightarrow x = \frac{54.84}{12}$$\;\Rightarrow x = 4.57$ThusTo simplify the fraction, change the decimal number to a form which has 10 raised to the power by moving the decimal position to the right until you get a whole number.Multiply that whole number by 10 raised to the power negative of the number of times you moved to the right Thus $58.84 = 5884 \times 10^{-2}$ NOTE:The power is negative if you moved to the right and positive if you move to the left$\Rightarrow x = \frac{54.84}{12} = \frac{5884 \times 10^{-2}}{12}$Using long division to simplify,$\Rightarrow \frac{5884 \times 10^{-2}}{12} = 457 \times 10^{-2}$Now change $457 \times 10^{-2}$ back to decimal.457 is the same as 457.0 , thus every whole number has point zero decimalSince the 10 is raised to the power -2 , we move the decimal point to the left 2 times, which gives us 4.57Alternatively, you can multiply each of the possible answers by 12 and the one that gives you the total cost of the 12 books (GH₵ 54.84) is the answer.