Satpal walks ²/₃ km from a place P, towards east and then from there 1⁵/₇ km towards west. Where will he be now from P?

We need to subtract the two distances.

Since $1\frac{5}{7}>\frac{2}{3}$, Ahmed's final location will be to the West of his initial position.
Distance between initial and final positions = $1\frac{5}{7} -\frac{2}{3} =\frac{12}{7} -\frac{2}{3}=\frac{36-14}{21} \mathrm{km}=\frac{22}{21} \mathrm{km}=1\frac{1}{21} \mathrm{km}$