Mr. Jensen bought some pens at a school supply store, including 15 black pens. 30% of all the pens he bought were black.
How many pens did Mr. Jensen buy in all?

Why did the ice arena get so hot after the big game (this is math related google it to find the paper

Needmax 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.

Which of these tools or constructions is used to inscribe a hexagon inside a circle?