A bag contains white, black and red balls only. A ball is drawn at random from the bag. The probability of getting a white ball is 3 10 and that of a black ball is 2 5 . Find the probability of getting a red ball. If the bag contains 20 black balls, then find the total number of balls in the bag.

Given, the probability of white ball, P w = 3 10 , The probability of getting a black ball, P b = 2 5 . As, we know the total sum of happening and not happening of an event is always one. Therefore, the probability of getting a red ball, P r = 1 - P w - P b = 1 - 3 10 - 2 5 = 3 10 . Let, the total number of balls be x . Then, the probability of getting a black ball = Number of black balls Total number of balls = 20 x Therefore, P b = 2 5 = 20 x ⇒ x = 20 × 5 2 = 50 Hence, the probability of getting a red ball is 3 10 , and the total number of balls is 50 .

A bag contains white, black and red balls only. A ball is drawn at random from the bag. The probability of getting a white ball is 3 10 and that of a black ball is 2 5 . Find the probability of getting a red ball. If the bag contains 20 black balls, then find the total number of balls in the bag.

Given, the probability of white ball, P w = 3 10 , The probability of getting a black ball, P b = 2 5 . As, we know the total sum of happening and not happening of an event is always one. Therefore, the probability of getting a red ball, P r = 1 - P w - P b = 1 - 3 10 - 2 5 = 3 10 . Let, the total number of balls be x . Then, the probability of getting a black ball = Number of black balls Total number of balls = 20 x Therefore, P b = 2 5 = 20 x ⇒ x = 20 × 5 2 = 50 Hence, the probability of getting a red ball is 3 10 , and the total number of balls is 50 .

MEDIUM

10th ICSE

IMPORTANT

Earn 100

A bag contains white, black and red balls only. A ball is drawn at random from the bag. The probability of getting a white ball is $\frac{3}{10}$ and that of a black ball is $\frac{2}{5}$ . Find the probability of getting a red ball. If the bag contains $20$ black balls, then find the total number of balls in the bag.

Important Questions on Probability

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10th ICSE

IMPORTANT

All In One ICSE Mathematics Class 10>Chapter 21 - Probability>CHAPTER EXERCISE>Q 60

A traffic signal displays green light for two minutes to allow passage of traffic on a particular road. If the signal is currently displaying green light, then find the probability that it will turn red within the next half a minute.

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10th ICSE

IMPORTANT

All In One ICSE Mathematics Class 10>Chapter 21 - Probability>CHAPTER EXERCISE>Q 61

There are

1000

sealed envelopes in a box,

10

of them contain a cash prize of

₹ 100

each,

100

of them contain a cash prize of

₹ 50

each and

200

of them contain a cash prize of

₹ 10

each and rest do not contain any cash prize. If they are well-shuffled and an envelope is picked up out, what is the probability that it contains no cash prize? (Write answer in decimal format)

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10th ICSE

IMPORTANT

All In One ICSE Mathematics Class 10>Chapter 21 - Probability>CHAPTER EXERCISE>Q 62

A number

x

is selected at random from the numbers

1, 4, 9, 16

and another number

y

is selected at random from the numbers

1, 2, 3, 4

. Find the probability that the value of

x \times y

is more than

16

EASY

10th ICSE

IMPORTANT

All In One ICSE Mathematics Class 10>Chapter 21 - Probability>CHALLENGERS>Q 1

The probability the minute hand lies from

5

15

min in a wall clock is

MEDIUM

10th ICSE

IMPORTANT

All In One ICSE Mathematics Class 10>Chapter 21 - Probability>CHALLENGERS>Q 2

The diameters of a circles (in

mm

) drawn on a table are given below. If a circle is chosen at random, then the probability that chosen circle has diameter less than

28

Diameters	$14 - 20$	$21 - 27$	$28 - 34$	$35 - 41$	$42 - 48$
Number of circles	$3$	$5$	$8$	$11$	$7$

MEDIUM

10th ICSE

IMPORTANT

All In One ICSE Mathematics Class 10>Chapter 21 - Probability>CHALLENGERS>Q 3

The diameters of circles (in $mm$ ) drawn on a table are given below:

Diameters	$14 - 20$	$21 - 27$	$28 - 34$	$35 - 41$	$42 - 48$
Number of circles	$3$	$5$	$8$	$11$	$7$

If a circle is chosen at random, then find the probability that chosen circle has radius lying between $14$ to $17$ .

MEDIUM

10th ICSE

IMPORTANT

All In One ICSE Mathematics Class 10>Chapter 21 - Probability>CHALLENGERS>Q 4

The diameters of circles (in $mm$ ) drawn on a table are given below:

Diameters	$14 - 20$	$21 - 27$	$28 - 34$	$35 - 41$	$42 - 48$
Number of circles	$3$	$5$	$8$	$11$	$7$

If a circle is chosen at random, then find the probability that chosen circle has diameter above $50$ .

MEDIUM

10th ICSE

IMPORTANT

All In One ICSE Mathematics Class 10>Chapter 21 - Probability>CHALLENGERS>Q 7

In the given figure, points $A, B, C$ and $D$ are the centres of four circles that each have a radius of length one unit. If a point is selected at random from the interior of square $A B C D$ , then the probability that the point will be chosen from the shaded region, is

Question Image

A bag contains white, black and red balls only. A ball is drawn at random from the bag. The probability of getting a white ball is 310 and that of a black ball is 25. Find the probability of getting a red ball. If the bag contains 20 black balls, then find the total number of balls in the bag.

Important Questions on Probability

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