Solve the following quadratic equation for x:

How many terms of the A.P. 65, 60, 55,… be taken so that their sum is zero?

a box consists of 100 shirts of which 88 are good, 8 have minor defects and 4 have major defects. Ramesh, a shopkeeper will buy only those shirts which are good but ‘Kewal’ another shopkeeper will not buy shirts with major defects. A shirt is taken out of the box at random. What is the probability that

(i) Ramesh will buy the selected shirt?

(ii) ‘Kewal’ will buy the selected shirt?

A toy is in the form of a cone of base radius 3.5 cm mounted on a hemisphere of base diameter 7 cm. If the total height of the toy is 15.5 cm, find the total surface area of the toy.

The sum of three numbers in A.P. is 12 and sum of their cubes are 288. Find the numbers.