Respuesta :
Answer:
Therefore 65 red balls must be added in the box.
Step-by-step explanation:
Probability:
The ratio of the number of the favorable outcomes to the total number of all possible outcomes.
[tex]Probability=\frac{\textrm{Number favorable outcomes}}{\textrm{Total number of outcomes}}[/tex]
Given that, A box contains some balls. There are 6 white ball, 8 black ball and 5 red ball in the box.
Let, x number of red red must be added in the box.
Now total number of balls=(6+8+5+x)=19+x
Number of red balls= (5+x)
The probability that a red ball is drawing is
[tex]=\frac{\textrm{Number of red ball}}{\textrm{Number of total ball}}[/tex]
[tex]=\frac{5+x}{19+x}[/tex]
According to the problem,
[tex]\frac{5+x}{19+x}=\frac56[/tex]
[tex]\Rightarrow 6(5+x)=5(19+x)[/tex]
⇒30+6x=95 +5x
⇒6x-5x=95-30
⇒x=65
Therefore 65 red balls must be added in the box.
