Answer:
2 hrs, 24 min
Step-by-step explanation:
Sally: in one hour, she can paint 1/4 of the room.
Joe: in one our, he can paint 1/6 of the room
Hour one: 1/4+1/6=3/12+2/12=5/12
1÷5/12=1*12/5=12/5
12/5= 2 & 2/5 hours, or 2.4 hours, or 2 hrs 24 minutes
Answer:
a)
And we can find this probability using the normal standard table or excel and we got:
b)
And we can find this probability using the complement rule and the normal standard table or excel and 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".
Part a
Let X the random variable that represent the time for the step 1 and Y the time for the step 2, we define the random variable R= X+Y for the total time and the distribution for R assuming independence between X and Y is:
Where and
We are interested on this probability
And the best way to solve this problem is using the normal standard distribution and the z score given by:
If we apply this formula to our probability we got this:
And we can find this probability using the normal standard table or excel and we got:
Part b
And we can find this probability using the complement rule and the normal standard table or excel and we got:
When you see a "%" you need to ask " a percent of what"?
Here, it's a percent of the original prize, so the discount is 20% of the original prize, that is 20% of 35.
20% is also 20/100 or 1/5, so we can calculate this like this:
so the discount is 7 dollars.
Answer:
x = 4
Step-by-step explanation:
Find 8 on the y-axis. Draw a horizontal line through y =8. Determine the x value for which the graph intersects this horizontal line y = 8. It is x = 4