Advertisements
Advertisements
प्रश्न
A box contains 90 discs which are numbered from 1 to 90. If one disc is drawn at random from the box, find the probability that it bears (i) a two-digit number, (ii) a number divisible by 5 ?
उत्तर
Total number of the discs which are numbered from 1 to 90 = 90
∴ Total number of outcomes = 90
(i) Let A be the event that one disc drawn at random from the box bears a two-digit number.
Number of discs that bears a two-digit number = 90 − 9 = 81
Favourable number of outcomes = 81
∴ P(A) =\[\frac{\text{Favourable number of outcomes}}{\text{Total number of outcomes}} = \frac{81}{90} = \frac{9}{10}\]
(ii) Let B be the event that one disc drawn at random from the box bears a number divisible by 5.
The outcomes in favour of the event B are 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85 and 90.
Favourable number of outcomes = 18
∴ P(B) =\[\frac{\text{Favourable number of outcomes}}{\text{Total number of outcomes}} = \frac{18}{90} = \frac{1}{5}\]
APPEARS IN
संबंधित प्रश्न
Two dice, one blue and one grey, are thrown at the same time.
(i) Write down all the possible outcomes and complete the following table:
| Event : ‘Sum on 2 dice’ |
2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 |
| Probability | `1/36` | `5/36` | `1/36` |
In a simultaneous throw of a pair of dice, find the probability of getting a sum less than 6
A bag contains cards which are numbered from 2 to 90. A card is drawn at random from the bag. Find the probability that it bears a number which is a perfect square
What is the probability that a number selected at random from the number 1,2,2,3,3,3, 4, 4, 4, 4 will be their average?
12 defective pens are accidently mixed with 132 good ones. It is not possible to just look at pen and tell whether or not it is defective. one pen is taken out at random from this lot. Determine the probability that the pen taken out is good one.
A card is drawn at random from a well-shuffled pack of 52 cards. Find the probability of getting
(i) a red king.
(ii) a queen or a jack.
Fill in the blank:
The sum of probabilities of all the outcomes of an experiment is ....... .
A die is rolled twice. Find the probability that 5 will not come up either time.
In a game, the entry fee is Rs 5. The game consists of a tossing a coin 3 times. If one or two heads show, Sweta gets her entry fee back. If she throws 3 heads, she receives double the entry fees. Otherwise she will lose. For tossing a coin three times, find the probability that she just gets her entry fee.
An unbiased coin is tossed twice. Find the probability of getting exactly one tail.
