Advertisements
Advertisements
प्रश्न
A jar contains 54 marbles, each of which some are blue, some are green and some are white. The probability of selecting a blue marble at random is `1/3` and the probability of selecting a green marble at random is `4/9`. How many white marbles does the jar contain?
उत्तर
Total number of marbles = 54.
It is given that, P(getting a blue marble) = `1/3` and P(getting a green marble) =`4/9`
Let P(getting a white marble) be x.
Since, there are only 3 types of marbles in the jar, the sum of probabilities of all three marbles must be 1.
`therefore 1/3 + 4/9 + x = 1 `
`⇒ (3 +4)/9 + x = 1`
`⇒ x = 1 - 7/9`
`⇒ x = 2/9`
`therefore P("getting a while marble")=2/9 ..........(1)`
Let the number of while marbles be n.
Then, P(getting a while marble) =`n/54 ........(2)`
From (1) and (2),
`n/54 = 2/9`
`rArr n = (2xx54)/9`
⇒ n = 12
Thus, there are 12 white marbles in the jar.
APPEARS IN
संबंधित प्रश्न
A die is thrown, then find the probability of the following events:
A is an Event: getting an odd number on the top upper surface of the die.
B is an Event: getting a perfect square on the upper surface of the die.
Two different dice are tossed together. Find the probability
(i) that the number on each die is even.
(ii) that the sum of numbers appearing on the two dice is 5.
All the red face cards are removed from a pack of 52 playing cards. A card is drawn at random from the remaining cards, after reshuffling them. Find the probability that the drawn card is of red colour.
Three different coins are tossed together. Find the probability of getting exactly two heads.
Two different dice are rolled together. Find the probability of getting the sum of numbers on two dice to be 5.
Two different dice are tossed together. Find the probability :
1) of getting a doublet
2) of getting a sum 10, of the numbers on the two dice.
A target shown in Fig. below consists of three concentric circles of radii, 3, 7 and 9 cm
respectively. A dart is thrown and lands on the target. What is the probability that the dart will land on the shaded region?
Two different dice are rolled simultaneously. Find the probability that the sum of numbers appearing on the two dice is 10 ?
A bag contains 3 red balls and 5 black balls. A ball is draw at random from the bag. What is the probability that the ball drawn is not red?
A black die and a white die are thrown at the same time. Write all the possible outcomes. What is the probability? that the product of numbers appearing on the top of the dice is less than 9.
All the black face cards are removed from a pack of 52 cards. The remaining cards are well shuffled and then a card is drawn at random. Find the probability of getting red card
All kings and queens are removed from a pack of 52 cards. The remaining cards are well shuffled and then a card is randomly drawn from it. Find the probability that this card is a black card.
In a bag there are 44 identical cards with figure of circle or square on them. There are 24 circles, of which 9 are blue and rest are green and 20 squares of which 11 are blue and rest are green. One card is drawn from the bag at random. Find the probability that it has the figure of green
In a bag there are 44 identical cards with figure of circle or square on them. There are 24 circles, of which 9 are blue and rest are green and 20 squares of which 11 are blue and rest are green. One card is drawn from the bag at random. Find the probability that it has the figure of green colour
A number is selected at random from the numbers 3, 5, 5, 7, 7, 7, 9, 9, 9, 9 The probability that the selected number is their average is
In a family of 3 children, the probability of having at least one boy is
A card is drawn at random from a well-shuffled pack of 52 cards. Find the probability that the card drawn is neither a red card nor a queen.
A bag contains 4 red and 6 black balls. A ball is taken out of the bag at random. What is the probability of getting a black ball?
Two coins are tossed together. Find the probability of getting: at least one head
A dice is rolled once. What is the probability that the number on top will be a factor of 36
