Aferry makes a trip from a port in one city to a port in another city in 30 minutes. the distance traveled s, in miles, t minutes after departing the first port is given by s(t)= -0.00077t^3 +0.03351t^2 +0.069t. at what time was the ferry moving the fastest?

What is the common difference in the following arithmetic sequence? 7,3,-1,-5

George is 187 cm tall. his son, ralph, is 142 cm tall. who casts the longer shadow. george when the sun is 65° above the horizon, or ralph when the sun is 56° above the horizon? how much longer? (nearest centimeter)

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?