There are 20 cards. Ten of these cards have the letter `"I"` printed on them and the other 10 have the letter `"T"` printed on them. If three cards picked up at random and kept in the same order, the probability of making word IIT is

In a survey of 400 youngsters aged 16-20 years, it was found that 191 have their voter ID card. If a youngster is seceted at random, find the probability that the youngster does not have their voter ID card

A hat contains a number of cards with 30% white on both sides, 50% black on one side and whit e on the other side, 20% black on both sides. The cards are mixed up, and a single card is drawn at random and placed on the table. Its upper side shows up black. The probability that its other side is also black is 2//9 b. 4//9 c. 2//3 d. 2//7

Two discharge tubes have identical material structure and the same gas is filled in them. The length of one tube is 10cm and that of th other tube is 20cm. Sparking starts in both the tubes when the potential difference between the cathode and the anode is 100 V . If the pressure in the shorter tube is 1.0 mm of mercury, what is the pressure in the longer tube?

(i) In how many ways can a pack of 52 cards be divided equally among four players? (ii) In how many ways can you divide these cards in four sets, three of them having 17 cards each and the fourth one just one card?