# 80 bulbs are selected at random from a lot and their life time (in hrs) is recorded in the form of a frequency table given below :

Life time (in hours) 300 500 700 900 1100

Frequency 10 12 23 25 10

One bulb is selected at random from the lot. The probability that its life is 1150 hours, is

a. 1/80

b. 7/16

c. 0

d. 1

**Solution:**

It is given that

Total bulb in a lot n(S) = 80

Number of bulbs whose life time is 1150 hours n(E) = 0

We know that

Probability that its life is 1150 hours = n(E)/n(S)

Substituting the values

= 0/80

= 0

Therefore, the probability that its life is 1150 hours is 0.

**✦ Try This:** Median of the following numbers : 2, 2, 5, 7, 4, 7, 7, 9, 1 is

**☛ Also Check:** NCERT Solutions for Class 9 Maths Chapter 14

**NCERT Exemplar Class 9 Maths Exercise 14.1 Problem 29**

## 80 bulbs are selected at random from a lot and their life time (in hrs) is recorded in the form of a frequency table given below : Life time (in hours) 300 500 700 900 1100 Frequency 10 12 23 25 10. One bulb is selected at random from the lot. The probability that its life is 1150 hours, is a. 1/80, b. 7/16, c. 0, d. 1

**Summary:**

80 bulbs are selected at random from a lot and their life time (in hrs) is recorded in the form of a frequency table. One bulb is selected at random from the lot. The probability that its life is 1150 hours, is 0

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