The minute hand of a clock is 7 in. Long how far does the point of the hand travel in 60 minutes?
1 answer:
Answer:
Step-by-step explanation:
60 minutes is one hour, which is all the way around the outside of the clock one time. This distance is represented by the circumference of a circle, assuming that the clock is in fact circular. The formula for the circumference of a circle in terms of the radius is
Our radius is 7, so the distance around the outside of that particular clock (and how far the minute hand travels if it goes around the clock one time) is
or
C = 14π
If you want the decimal equivalency for that, multiply in pi as 3.1415 and round to whatever place you need. In decimal form, that is
C = 43.9 inches
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Answer:
And if we solve for a we got
Step-by-step explanation:
Previous concepts
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".
Solution to the problem
Let X the random variable that represent the hourly rates of a population, and for this case we know the distribution for X is given by:
For this part we want to find a value a, such that we satisfy this condition:
(a)
(b)
Both conditions are equivalent on this case. We can use the z score again in order to find the value a.
As we can see on the figure attached the z value that satisfy the condition with 0.80 of the area on the left and 0.20 of the area on the right it's z=0.842. On this case P(Z<0.842)=0.8 and P(z>0.842)=0.20
If we use condition (b) from previous we have this:
But we know which value of z satisfy the previous equation so then we can do this:
And if we solve for a we got