ताश की एक गड्डी में से एक पत्ता खो गया है। शेष पत्तों में से दो पत्ते यादृच्छिक रूप से निकाले जाते हैं और वे दोनों हुकुम (spades) के पाए जाते हैं। खोए हुए पत्ते के हुकुम न होने की प्रायिकता है:

A box contains 'x + 4' red, 'x – 1' green and 'x – 5' blue balls. If two balls are drawn from the bag one after another without replacement, then the probability of getting one red and one green ball is equal to the probability of getting a sum equal to or more than 8 when two fair dice are rolled. Find the probability of drawing a red ball when one ball is drawn at random from the bag.

Four persons are chosen at random from a group containing 3 men, 2 women, and 4 children. The probability that exactly two of them are children is: