Stacy rowed across the lake with her friend Rainey (in the same boat) at a rate of 4 mph. On the way back, Rainey rowed the boat at a rate of 3 mph while Stacy rested. If the lake is 6 miles across, how long did it take them to complete their trip?
A. 3 1/2 hours

B. 4 1/2 hours

C. 4 1/6 hours

D. 2 7/10 hours

Could answer every question with steps

In triangle abc, the length of side ab is 12 cm, the length of side bc is 5 cm, and the length of side ca is 9 cm. find the measure of angle a using the law of cosines.

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?