Mean is just the average of all of them
So... 5 + 4 + 18 + 19 + 12 + 20 + 12 + 12 = 102
Then you divide that number by the amount of numbers you have so 102 / 8 = 12.75 or rounding it up to 13
For median you have to first put them in order from smallest to largest.
So 4 5 12 12 12 18 19 20
Then you have to find the middle number between them but in this case we have two... 12 and 12. Since they're the same number, the median is 12.
You can solve this one by adding their rates, but you have to invert the numbers they give you to find the rate. Rate is measured in something per unit of time, and "per" indicates division. So the rates are: 1/3 of an hour (Sally) and 1/6 of an hour (Steve). So add the rates: 1/3 + 1/6 = 1/2. (1/3 is 2/6, and 2/6 + 1/6 = 3/6). Since their combined rate is 1/2 of a room in one hour, it takes them two hours to paint the room.
This answer makes sense: It takes Sally three hours by herself; with Steve's help, she's faster, but not THAT much faster, because he's pretty slow. You can often spot-check word problem answers like this by giving it a common sense once-over. If we came up with four hours, that would clearly be wrong: it should take her LONGER if she's getting help.
Answer:
0.2.34
That is probs the answer for B
Answer:
-625
Step-by-step explanation:
The magnitude gets raised to the power, and the angle gets multiplied by the power:
5(cis7pi/4)^4 = (5^4)cis(4·7π/4) = 625cis(7π) = 625cis(π) = -625
