UPSC 2015 CDS I Math Paper

402+92=1681=412
So, the sides of the triangular fieldform a right-angled triangle whose hypotenuse is 41 m and the lengths of the other two sides are 40 m and 9 m.
Therefore, the number of rose beds that can be prepared in the field
=

1 2 ×4000×900

900

=2000