HELP PLEASE I DON'T UNDERSTAND
2 answers:
Answer:
Step-by-step explanation:
First thing you need to do is to check if the sample data has also that 40% cycling boys, since the information you are given is not exact is "about 40%".
I did it counting in excel so not to miscount by accident, and the result was 54 numbers bellow 4 and 150 total numbers.
That comes down to 54/150 or 0.36, so in this particular set of data only 36% of the boys commute by cycle.
Now, this gives us a probability of 36% of finding a boy who commutes by bicycle on the first pick, but we want to know the probability of 3 failures and then a success. This is represented by p=0.36 and q=0.64, where q is the probability of failure on the first try.
This means that the event will occur on the first trial with probability p. If that fails, then it will occur on the next trial with a probability of (1−p)p or q*p. If that also fails, then continuing on, the probability of the event happening on the third trial is or
. If we go on and on we can see that the probability of the first success on the nth trial is
or
. If n=4 then the probability would be:
P=6.04%
You might be interested in
14 of the machine that cost $150 was sold and 8 of the machine that cost $225 was sold.
To solve this problem, we would write a system of linear equations.
- Let x represent the machine that cost $150
- Let y represent the machine that cost $225
We can proceed to write our equations now.
From equation 1
put equation (iii) into (ii)
Since we know the number of y, we can simply substitute it into equation (i) and solve.
From the calculations above, 14 of the machine that cost $150 was sold and 8 of the machine that cost $255 was sold.
Learn more about system of equations here;