Probability
- The letters B, G, I, N, R are rearranged to form the word 'BRING'. Find its probability ?
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The five letters could be arrange in 5! ways.
One of them is 'BRING'.Correct Option: A
The five letters could be arrange in 5! ways.
One of them is 'BRING'.
∴ Required probability = 1/5!
= 1/(5 x 4 x 3 x 2 x 1)
= 1/120
- What is the probability that a card drawn at random from a pack of 52 cards is either a king or a spade?
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Required probability
= 3/52 + 13/52 = 16/52 =4/13Correct Option: B
Required probability = 3/52 + 13/52 = 16/52 =4/13
[Hint Why 13/52 because there are 13 spades and why 3/52 instead of 4/52 (there are four kings) because one king is already counted in spades.]
- If three unbiased coins are tossed simultaneously, then the probability of exactly two heads, is
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n(S) = 23 = 8
Let E = Event of getting exactly two heads
= {(H, H, T), (H, T ,H), (T, H, H)}Correct Option: C
n(S) = 23 = 8
Let E = Event of getting exactly two heads
= {(H, H, T), (H, T ,H), (T, H, H)}
⇒ n(E) = 3
∴ required probability = 3/8
- A card is drawn from a well-shuffled pack of cards. The probability of getting a queen of club or a king of heart is ?
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Total ways = 52
There is one queen of club and one king of heart.
∴ Favorable ways = 1 + 1 = 2
Correct Option: B
Total ways = 52
There is one queen of club and one king of heart.
∴ Favorable ways = 1 + 1 = 2
∴ Required probability = 2/52 = 1/26
Direction: Study the information carefully to answer the question that follow.
A basket contains 3 blue, 2 green and 5 red balls.
- If three balls are picked at random, what is the probability that atleast one is red ?
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Total Number of outcomes = 10C3 = 120
Number of outcomes not containing red balls = 5C3 = 10
∴ Probability that at least one is red = 1 - 10/120Correct Option: C
Total Number of outcomes = 10C3 = 120
Number of outcomes not containing red balls = 5C3 = 10
∴ Probability that at least one is red = 1 - 10/120 = 11/12