Question

a box has 390 bulbs .out of this 26 are defective .a bulb is chosen at random .find probability of bulb chosen not being defective

Answer 1

Defective bulbs = 26
Non defective bulbs = 364
Probability of a non-defective bulb = 364 / 390
= 0.933

Answer 2

P(getting a bulb is not defective) =$\dfrac{182}{195}$ or 0.933.

Step-by-step explanation:

Given,

Total number of bulbs in a box = 390 and

Number of defective bulbs in a box = 26

To find, the probability of bulb chosen not being defective = ?

∴ Total number of outcomes = 390

Number of non-defective bulbs in a box = 390 - 26 = 364

The favourable outcomes = 364

∴ P(getting a bulb is not defective) = $\dfrac{Number of favourable outcomes}{Total number of possible outcomes}$

P(getting a bulb is not defective) = $\dfrac{364}{390} =\dfrac{182}{195}$ or 0.933

Hence, P(getting a bulb is not defective) =$\dfrac{182}{195}$ or 0.933.