In a class, there are 15 boys and 10 girls. Three students are selected at rando

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Question
In a class, there are 15 boys and 10 girls. Three students are selected at random. The probability that 1 girl and 2 boys are selected, is:
Options
A. 21/46
B. 1/5
C. 3/25
D. 1/50

Correct Answer

21/46

Explanation

Let S be the sample space and E be the event of selecting 1 girl and 2 boys.

Then, n(S) = Number ways of selecting 3 students out of 25

= $25 C_{3}$ = 2300.

n(E)= $10 C_{1} * 15 C_{2}$ = 1050.

P(E) = n(E)/n(s) = 1050/2300 = 21/46

Probability problems

Search Results

1. A six-sided die with faces numbered 1 through 6 is rolled three times. What is the probability that the face with the number 6 on it will not face upward on all the three rolls?
Options
A. 215/216
B. 1/216
C. 215/256
D. 1/52

2. Find the probability that one ball is white when two balls are drawn at random from a basket that contains 9 red, 7 white and 4 black balls.
Options
A. 18/95
B. 18/190
C. 1/2
D. 91/190

3. One card is drawn from deck of 52 cards, each of the 52 cards being equally likely to be drawn. Find the probability that the ball drawn is red.
Options
A. 1/3
B. 1/2
C. 1/4
D. 1/6

4. Find the probability of selecting exactly 2 children when four persons are choosen at random from a group of 3 men, 2 woman and 4 children.
Options
A. 9/29
B. 10/21
C. 12/21
D. 14/19

5. What is the probability that a couple with four children have atleast one girl?
Options
A. 0.0625
B. 0.9375
C. 0.5
D. 0.0257

6. What is the probabiltiy of getting a mutliple of 2 or 5 when an unbiased cubic die is thrown?
Options
A. 1/3
B. 1/2
C. 2/3
D. 1/6

7. What is the probability that it is either a heart card or diamond card, when a card is drawn from a well shuffled standard pack of 52 playing cards?
Options
A. 1
B. 1/2
C. 3/4
D. 1/3

8. From well shuffled standard pack of 52 playing cards,one card is drawn. What is the probability that it is either a red card or black card?
Options
A. 1/2
B. 3/4
C. 1
D. 1/3

9. Find the probability that it is either white or red ball when,one ball is drawn at random in a bag that contains 3 black,4 white and 5 red balls
Options
A. 0.5
B. 0.75
C. 0.25
D. 0.8

10. The odds favouring the event of a person hitting a target are 3 to 5. The odds against the event of another person hitting the target are 3 to 2. If each of them fire once at the target, find the probability that both of them hit the target.
Options
A. 1/20
B. 4/20
C. 1/20
D. 3/20

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