**Find Probability of an Event Examples :**

Here we are going to see some practice questions on probability.

**Question 1 :**

A company manufactures 10000 Laptops in 6 months. Out of which 25 of them are found to be defective. When you choose one Laptop from the manufactured, what is the probability that selected Laptop is a good one.

**Solution : **

Number of laptops n(S) = 10000

Number of defective lap top = 25

Let "A" be the event of choosing good laptop.

Number of good laptop = 10000 - 25

n(A) = 9975

p(A) = n(A)/n(S)

p(A) = 9975/10000

p(A) = 0.9975

**Question 2 :**

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

**Solution :**

Total number of youngster n(S) = 400

Let "A" be the event of choosing youngster does not have ID card

= 400 - 191

n(A) = 209

P(A) = n(A)/n(S)

P(A) = 209/400

**Question 3 :**

The probability of guessing the correct answer to a certain question is x/3 . If the probability of not guessing the correct answer is x/5, then find the value of x.

**Solution :**

P(A) = Probability of getting correct answer

p(B) = Probability of getting not guessing correct answer

P(A) + p(B) = 1

(x/3) + (x/5) = 1

(5x + 3x)/15 = 1

8x = 15

x = 15/8

**Question 4 :**

If a probability of a player winning a particular tennis match is 0.72. What is the probability of the player loosing the match?

**Solution :**

Let "A" be event of winning a game. A bar be the event of lossing the game.

p(A) + p(A bar) = 1

0.72 + p(A bar) = 1

p(A bar) = 1 - 0.72

p(A bar) = 0.28

**Question 5 :**

1500 families were surveyed and following data was recorded about their maids at homes

A family is selected at random. Find the probability that the family selected has (i) Both types of maids (ii) Part time maids (iii) No maids

**Solution :**

Total number of families n(S) = 1500

Let "A" be the event of selecting maid of both types.

n(A) = 250

p(A) = n(A)/n(S)

p(A) = 250/1500

p(A) = 1/6

(ii) Part time maids

Let "B" be the event of selecting maid of part time

n(B) = 8600

p(B) = n(B)/n(S)

p(B) = 860/1500

p(B) = 43/75

(iii) No maids

Number of families selected maid = 860 + 370 + 250

= 1480

n(C) = 1500 - 1480

n(C) = 20

P(C) = n(C)/n(S)

= 20/1500

p(C) = 1/75

After having gone through the stuff given above, we hope that the students would have understood, "Find Probability of an Event Examples"

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