Question

A cartoon of 24 bulb contain 6 defective bulbs , one bulb drawn at random . What is the probability that the bulb is not defective? if the bulb is not replaced and second bulb is selected at random from rest , what is the probability that the bulb is defective? what is the probabilty that number selected from 1, 2, 3 ......25 is a number divisible by 3 and 4.? someone asked to take a number frm 1 to 100 ,find the probability that it is a prime number? a bag contains 5 white, 7 red and 2 blue . one ball is drawn at random frm bag. what is the probability that ball drawn is : (a ) white or blue (b) blue or red (c) not white (d) neither blue nor white. as number of trials in an experiment goes on increasing we may expect the experimental and theoretical probability to the nearly the same. Comment on it. a box contains 50 bolts and 150 nuts . half of the bolts and half of the nuts are rusted . if one item is choosen frm box at random . what is the probability that it is rusted or a bolt? find the probability of getting 53 Mondays in a leap year, 53 tuesdays in non-leap year? two coins are tossed once. find the probability of getting (a) exactly one head (b) almost one head. 15 cards numbered 1, 2, 3, .....15 are put in a box and shuffled thoroughly. a card is drawn at random frm box. find the probability that the card drawn bears (a) even number (b) number divisible by 2 or 3.?

Answer 1

Please remember that Maximum portability is 1. So we can get total probability of non defective bulbs and subtract it form 1 to get total probability of defective bulbs. So here we go, Total cases of non defective bulbs 16C2=16∗152∗1=120total cases = 20C2=20∗192∗1=190probability = 120190=1219P of at least one defective = 1−1219=719