Solve the following for

A box contains cards numbered 6 to 50. A card is drawn at random from the box. Calculate the probability that the drawn card has a number which is a perfect square.

If π is taken as 22/7, calculate the distance (in metres) covered by a wheel of diameter 35 cm, in one revolution.

Find the number of all three-digit natural numbers which are divisible by 9.

In Fig. 2, two circles touch each other at the point C. Prove that the common tangent to the circles at C, bisects the common tangent P and Q.