A pipe can fill a cistern in 10 hours. Due to a leak in the bottom it is filled in 12 hours. When the cistern is full, in how much time will it be emptied by the leak?

Two cards are drawn from a well shuffled pace of 52 cards. Find the probability that

(1) both the cards are of different colour
(2) both the cards are face cards
(3) one of the two cards is a king.

अवैधिक व्यवस्थातंत्र वैधिक व्यवस्थातंत्र का अंग है ।