A biased 3-coloured spinner was spun 240 times. It landed on Red n times, on Orange 3n times and on Yellow 8n times.
If you spin this spinner 1000 times, how many times do you expect it to land on Red?
(Hint: Find n first)

Respuesta :

Given:

A biased 3-colored spinner was spun 240 times. It landed on Red n times, on Orange 3n times and on Yellow 8n times.

To find:

The expected number of times it land on Red if you spin this spinner 1000 times.

Solution:

A biased 3-colored spinner was spun 240 times. It landed on Red n times, on Orange 3n times and on Yellow 8n times. So,

[tex]n+3n+8n=240[/tex]

[tex]12n=240[/tex]

[tex]n=\dfrac{240}{12}[/tex]

[tex]n=20[/tex]

The value of n is 20. It means the spinner land on red 20 times if the spinner was spun 240 times. So, the probability of getting red is:

[tex]P(Red)=\dfrac{20}{240}[/tex]

[tex]P(Red)=\dfrac{1}{12}[/tex]

If you spin this spinner 1000 times, then the expected number of times to getting red is:

[tex]E(Red)=1000\times P(Red)[/tex]

[tex]E(Red)=1000\times \dfrac{1}{12}[/tex]

[tex]E(Red)=83.333...[/tex]

[tex]E(Red)\approx 83[/tex]

Therefore, the expected number of times to land on red is 83.