A solid sphere of radius 9 cm is melted to form a sphere of radius 6 cm and a right circular cylinder of same radius. The height of the cylinder so formed is

A pilot in an aeroplane at an altitude of 200 m observes two points lying on either side of a river. If the angles of depression of the two points be 45° and 60°, then the width of the river is

AB is the diameter of a circle with center O and P be a point on its circumference. If ∡POA = 120°, then the value of ∡PBO is

Which of the set of three sides can't form a triangle?

If x = x2+11 2 - 2, then x3 + 5x2 + 12x is

If x = a + 1a, y = a - 1a ,(a>0), then the value of x4+y4-2x2y2 is

The average marks obtained by a class of 60 students is 65. The average marks of half of the students is found to be 85. The average marks of the remaining students is

Which one of the following is the minimum value of the sum of two integers whose product is 24?