Farah rolls a fair dice and flips a fair coin. What is the probability of obtaining a 5 and a head?
1 answer:
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1) 1/8
2) 1/2
Step-by-step explanation:
1)
First of all, we notice that the spinner is divided into 8 sections of equal size.
So the number of sections is
n = 8
Secondly, we note that each section has the same size: this means that the probability of the spinner landing on each section is the same.
The probabilty of a certain event A to occur is given by
where
a is the number of successfull outcomes (in which A occurs)
n is the total number of possible outcomes
Here we want to find
= probability that the spinner lands on section 7
Here we have:
(only 1 outcome is successfull: the one in which the spinner lands on section 7)
Therefore, the probability is
2)
Here we want to find the probability that the spinner lands on an even numbered section.
As before, the total number of possible outcomes his:
which corresponds to: 1, 2, 3, 4, 5, 6, 7, 8
The even-numbered sections are:
2, 4, 6, 8
So, the number of successfull outcomes is
Because there are only 4 even-numbered sections.
Therefore, the probability that the spinner lands on an even numbered section is: