Question

a bag contains 7 red red balls and some blue balls if the probability of drawing blue balls is triple that of a red ball determine the numbers of blue balls in the bag​

Answer 1

Answer:

Let number of blue balls in the bag =x

Total no of balls in bag =5+x  [No. of redball =5]

Probability of drawing a blue ball =  

Total no of ball

No. of blue ball

​  

 

P(B)=  

5+x

x

​  

 

Probability of drawing a Red ball =  

Total no of ball

No. of red ball

​  

 

P(R)=  

5+x

5

​  

 

Given,

P(B)=2P(R)

5+x

x

​  

=2(  

5+x

5

​  

)

x=10

​  

 

Hence, no. of blue balls in the bag =10.

Step-by-step explanation:

Answer 2

Given that:

• A bag contains 7 red balls and some blue balls.
• The probability of drawing blue balls is triple that of a red ball.

Let us assume:

• A bag contains x blue balls.
• Total number balls in the bag = 7 + x

To Find:

• The number of blue balls in the bag.

Formula used:

• P(E) = F/T

Where,

• P = Probability
• E = Events
• F = Favourable outcomes
• T = Total outcomes

Now we have,

• Total outcomes = 7 + x
• Favourable outcomes for blue ball = x
• Favourable outcomes for red ball = 7

According to the question.

P(drawing a blue ball) = 3 × P(drawing a red ball)

ㅤ↠ㅤx/(7 + x) = 3 × 7/(7 + x)

Cancelling (7 + x) both sides.

ㅤ↠ㅤx = 3 × 7

ㅤ↠ㅤx = 21

Hence,

• There are 21 blue balls in the bag.