The school pool needs to be refilled after emptying it for winter cleaning .water flowing through both a small pipe and large pipe can fill the pool in 7 hours. water flowing through the small pipe alone can fill the tank in 18 hours . how many ours would it take to fill the tank using only the large pipe?

Ateacher has $80 to buy workbooks. each work book cost $3. if she buys as many workbooks as possible, how much money does she have leftover? a) $2 b) $4 c) $6 d) $8

Now max recorded the heights of 500 male humans. he found that the heights were normally distributed around a mean of 177 centimeters. which statements about max’s data must be true? a) the median of max’s data is 250 b) more than half of the data points max recorded were 177 centimeters. c) a data point chosen at random is as likely to be above the mean as it is to be below the mean. d) every height within three standard deviations of the mean is equally likely to be chosen if a data point is selected at random.

If cos(2x) = tan^2(y), show that cos(2y) = tan^2(x).