CBSE Mathematics Practice Paper 2013 Set 1, given here.
29. The angle of elevation of a jet fighter from a point A on the ground is 600. After a fight at a speed of 648 km/hour, find the constant height at which the jet is flying.
30. A two digit number is such that the product of its digits is 15. If 18 is added to the number, the digit interchange their places. Find the number.
31. The coordinates of the cancroids of a triangle are (1, 3) and two of its vertices are (-7, 6) and (8, 5). Find the third vertex. Also, find the coordinates of the centroid of the triangle when the third vertex is (2, 4).