If 4 is 1/2 what is the whole?

2people are trying different phones to see which one has the better talk time. chatlong has an average of 18 hours with a standard deviation of 2 hours and talk-a-lot has an average of 20 hours with a standard deviation of 3. the two people who tested their phones both got 20 hours of use on their phones. for the z-scores i got 1 for the chatlong company and 0 for talk-a-lot. what is the percentile for each z-score?

Table which ratio is equivalent to 3: 7? 6: 7 3: 21 24: 56 15: 30

How do you write something in scientific notation?