Gerry is a member of a book club. he gets 2 books for free for every 7 books he buys. if gerry bought 21 books last year, how many books did he get free?

Atrain leaves little? rock, arkansas, and travels north at 90 kilometers per hour. another train leaves at the same time and travels south at 80 kilometers per hour. how long will it take before they are 680 kilometers? apart?

Compute the standard deviation of the following set of data to the nearest whole number. 10, 10, 15, 20, 25

Amayoral candidate would like to know her residents’ views on a tax on sugar drinks before the mayoral debates. she asks one thousand registered voters from both parties. these voters are an example of a census population convenience sample simple random sample