Question

Ravish's house is $\frac{9}{10}$ Km from his school. He walked some distance and then took a bus for $\frac{1}{2}$ Km up to the school. How far did he walk?

Answer 1

Total distance between the house and the school = $\frac{9}{10}\mathrm{km}$
Distance covered in the bus = $\frac{1}{2}\mathrm{km}$
Distance covered by walking + Distance covered in the bus = Total distance between the house and the school
Distance covered by walking = Total distance between the house and the school - Distance covered in the bus
Distance covered by walking:
$$\begin{gathered} \frac{9}{10}-\frac{1}{2} \\ \mathrm{LCM}\mathrm{of}10\mathrm{and}2\mathrm{is}10,\mathrm{so}\mathrm{we}\mathrm{convert}\mathrm{each}\mathrm{fraction}\mathrm{into}\mathrm{an}\mathrm{equivalent}\mathrm{fraction}\mathrm{with}\mathrm{denominator}10 \\ =\frac{9\times 1}{10\times 1}-\frac{1\times 5}{2\times 5}=\frac{9}{10}-\frac{5}{10} \\ =\frac{9-5}{10} \\ =\frac{4}{10}\mathrm{km} \\ =\frac{4÷2}{10÷2}=\frac{2}{5}\mathrm{km}(\mathrm{HCF}\mathrm{of}\mathrm{numerator}\&\mathrm{denominator}\mathrm{is}2) \end{gathered}$$