If A and B are square matrices of order 3 such that |A| = –1, |B| = 3, then find the value of |2AB|.

If A is an invertible square matrix of order 3 and |A| = 5, then find the value of |adj A|.
If the determinant of matrix A of order 3 × 3 is of value 4, write the value of |3A|.
Find the sum of the order and the degree of the following differential equations :
The radius r of a right circular cylinder is increasing at the rate of 5 cm/min and its height h, is decreasing at the rate of 4 cm/min. When r= 8 cm and h = 6 cm, find the rate of change of the volume of cylinder.
A box contains 50 bolts and 50 nuts. Half of the bolts and nuts are rusted. If two items are drawn with replacement, what is the probability that either both are rusted or both are bolts.
A balloon, which always remains spherical, has a variable diameter . Find the rate of change of its volume with respect to x.