Question

A spinner is divided into 8 sections of equal size. The sections are numbered 1 through 8.

Use this information to determine the probability of the needle landing on:


1.) Section 7

2.) an even numbered section

3.) Section 1, 2, 3, or 4

4.) Section 9

5.) Section 8

Answer 1

1) 0.125

2) 0.5

3) 0.5

4) 0.125

5) 0.125

Explanation:

Taking into account that the spinner is divided in sections of equal size, there is equal probability that the needle land on every of the 8 sections, so the probability that the needle land on section 7 is equal to:

`P=(1)/(8)=0.125`

Because, we have 8 possible sections and one of them is section 7.

At the same way, the probability that the needle land on section 9 is:

`P=(1)/(8)=0.125`

And the probability that the needle land on section 8 is:

`P=(1)/(8)=0.125`

On the other hand, there are 4 section with an even number so, the probability that the needle land on an even numbered section is:

`P=(4)/(8)=0.5`

Finally, the probability that the needle land on section 1, 2, 3 or 4 is the sum of the probability that the needle land on section 1, the probability that the needle land on section 2, the probability that the needle land on section 3 and the probability that the needle land on section 4, so it is equal to:

`P=(1)/(8)+(1)/(8)+(1)/(8)+(1)/(8)=(1)/(2)=0.5`