An aeroplane covers a certain distance at a speed of 240 kmph in 5 hours. To cover the same distance in 1 ²/₃ hours, it must travel at a speed of:

Explanation:-

$$\eqalign{ & {\text{Distance}} = \left( {240 \times 5} \right) = 1200\,{\text{km}} \cr & {\text{Speed}} = \frac{{{\text{Distance}}}}{{{\text{Time}}}} \cr & {\text{Speed}} = \frac{{1200}}{{\left( {\frac{5}{3}} \right)}}\,{\text{km/hr}}\, \cr & \left[ {{\text{We}}\,{\text{can}}\,{\text{write}}\,1\frac{2}{3}\,{\text{hours}}\,{\text{as}}\,\frac{5}{3}\,{\text{hours}}} \right] \cr & \therefore {\text{Required}}\,{\text{speed}} \cr & = \left( {1200 \times \frac{3}{5}} \right)\,{\text{km/hr}} \cr & = 720\,{\text{km/hr}} \cr}$$