You ordered 7 new reading books online. each book cost the same amount. you have to pay $12 for shipping and handling. the total bill (not including tax) was $89. how much did each book cost? HELP ASAP

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?