Question

In a box there are 10 non-defective and some defective bulbs. If the probability that a bulb selected at random from the box to be defective is 2/7 then find the number of defective bulbs.​

Answer 1

answer = 4

Step-by-step explanation:

let no. of defective bulbs be x

let total bulbs be 10+x

atq,

x/(10+x)=2/7

7x=20+2x

5x=20

x=4

hence no. of defective bulbs is 4