The function f(t) = 7 cos(pi over 4t) + 12 represents the tide in light sea. it has a maximum of 19 feet when time (t) is 0 and a minimum of 5 feet. the sea repeats this cycle every 8 hours. after two hours, how high is the tide?

Saline iv fluid bags cost $64.20 for 24, 1000 ml bags from one supplier. a new supplier sells 500 ml bags for $2 each. the hospital uses about 10,000, 1000 ml bags each month. nurses report that about half of the bags are more than half full when they are discarded. if you are going to use only one supplier, which size bag provides the best deal, and how much will you save each month? compare the cost of the new supplier to the current one.

After reading 80% of her e-mails in her inbox, danette still has m unread e-mails. which of the following expressions could represent the number of e-mails danette had in her inbox before she started reading? choose 2 answers: (choice a) 5m (choice b) 1.8m (choice c) 80m (choice d) m/0.8 (choice e) m/1−0.8

Is experimental probibilty the same as the observed frequency in math? i need the answer asap!