Calculate the common difference of the A.P.

A container, open at the top and made up of metal sheet is in the form of a frustum of a cone of height 16 cm with diameters of its lower and upper ends a s 16 cm and 40 cm respectively. Find the cost of metal sheet used to make the container, if it cost ₹10 per 100 cm². [Take π = 3.14]

Find the probability that a leap year selected at random, will contain 53 Mondays.

Three coins are tossed simultaneously. Find the probability of getting exactly two heads.

For what value of k, are the roots of the quadratic equation (k – 12) x² + 2 (k – 12) x + 2 = 0 equal?