If two students from this college are selected at random, what is the probability that they are both males?
1 answer:
Answer:
Step-by-step explanation:
Assuming this problem :"Only 30% of the students in a certain liberal arts college are males. If two students from this college are selected at random, what is the probability that they are both males?"
Previous concepts
An independent event is an "event that has no connection to another event's chances of happening ". For this case we can assume that if one person is male and if we select another one the probability that this one would be male or female is totally indepedent from the first selection.
When we have two independent events let's say A and B and we want to find the probability that both events occurs at the same time we can use the following formula:
Solution to the problem
We can define some notation:
first person selected is a male
second person selected is male
On this case we want the probability that both would be males. And we can express this like this on math terms:
For this case we can assume that the two events are independent. And in order to find the probability for two events independents events we just need to multiply the probabilities of each one like this:
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The answer is 16
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Drop comments if any doubt arises.
Answer:
Answer d)
,
, and
Step-by-step explanation:
Notice that there are basically two right angle triangles to examine: a smaller one in size on the right and a larger one on the left, and both share side "b".
So we proceed to find the value of "b" by noticing that it the side "opposite side to angle 60 degrees" in the triangle of the right (the one with hypotenuse = 10). So we can use the sine function to find its value:
where we use the fact that the sine of 60 degrees can be written as:
We can also find the value of "d" in that same small triangle, using the cosine function of 60 degrees:
In order to find the value of side "a", we use the right angle triangle on the left, noticing that "a" s the hypotenuse of that triangle, and our (now known) side "b" is the opposite to the 30 degree angle. We use here the definition of sine of an angle as the quotient between the opposite side and the hypotenuse:
where we used the value of the sine function of 30 degrees as one half:
Finally, we can find the value of the fourth unknown: "c", by using the cos of 30 degrees and the now known value of the hypotenuse in that left triangle:
Therefore, our answer agrees with the values shown in option d)