Question 30
Refer to Q.29. the probability that bulbs selected randomly from the lot have life less than 900 h, is:

A) $\frac{11}{40}$
B) $\frac{5}{16}$
C) $\frac{7}{16}$
D) $\frac{9}{16}$

Open in App

Solution

The answer is D.
Total number of bulbs in the lot, n(S) = 80
Number of bulbs whose life time is less than 900 h, n = 10 + 12 + 23 = 45
$∴$ Probabilitythat bulbs has life time less than 900 h $= \frac{n (E)}{n (S)} = \frac{45}{80} = \frac{9}{16}$

Suggest Corrections

Similar questions

Q. The probability that bulbs selected randomly from the lot has life less than 900 hours is :

Q. Fill In The Blanks

In Q.No. 5, the probability that a bulb selected at random from the the lot has life less than 900 hours is _________.

Question 29
80 bulbs are selected at random from a lot and their life time ( in hours) is recorded in the form of a frequency table given below:

$\begin{matrix} Lifetime (in hours) & 300 & 500 & 700 & 900 & 1100 Frequency & 10 & 12 & 23 & 25 & 10 \end{matrix}$

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

A) $\frac{1}{80}$
B) $\frac{7}{16}$
C) 0
D) 1

80 bulbs are selected at random from a lot and their lifetime in hours is recorded as under.

$\begin{matrix} Lifetime (in hours) & 300 & 500 & 700 & 900 & 1100 Frequency & 10 & 12 & 23 & 25 & 10 \end{matrix}$

Our bulb is selected at random from the lot. What is the probability that its life is 1150 hours?

(a) $\frac{1}{80}$

(b) $\frac{7}{16}$

(d) 0

Q. A number is randomly selected from the set

{6, 7, 8, 8, 8, 10, 10, 11}

. Find the probability the number will be less than the mean.

Join BYJU'S Learning Program

Question 30 Refer to Q.29. the probability that bulbs selected randomly from the lot have life less than 900 h, is: A) 1140 B) 516 C) 716 D) 916

The answer is D. Total number of bulbs in the lot, n(S) = 80 Number of bulbs whose life time is less than 900 h, n = 10 + 12 + 23 = 45 ∴ Probabilitythat bulbs has life time less than 900 h =n(E)n(S)=4580=916

Question 30
Refer to Q.29. the probability that bulbs selected randomly from the lot have life less than 900 h, is:

A) $\frac{11}{40}$
B) $\frac{5}{16}$
C) $\frac{7}{16}$
D) $\frac{9}{16}$

The answer is D.
Total number of bulbs in the lot, n(S) = 80
Number of bulbs whose life time is less than 900 h, n = 10 + 12 + 23 = 45
$∴$ Probabilitythat bulbs has life time less than 900 h $= \frac{n (E)}{n (S)} = \frac{45}{80} = \frac{9}{16}$