An aeroplane was flying at a height of $1600\mathrm{m}.$ From the time it started to land, it made a change of $70\mathrm{m}$in every minute. How many minutes will it take to descend to a height of $200\mathrm{m}?$

Division of integers:

The height of an aeroplane $=1600\mathrm{m}$

To descend a height of $200\mathrm{m}$ from the ground , it should descend a height of $1600-200=1400\mathrm{m}$

In one minute, it will descend to a height of $70\mathrm{m}$

Number of minutes taken by the aeroplane to descend to a height of $1400\mathrm{m}$ $=\frac{1400}{70}=20\mathrm{minutes}$

Hence, an aeroplane will take $20\mathrm{minutes}$to descend to a height of $200\mathrm{m}$.