Issac has 21 marbles and 7 blue marbles he wants to place them in identical group without any marbles left what is the greatest number of group isaac can make?

Can someone me with this problem . show your work .

Which of the following is most likely the next step in the series? a3z, b6y, c9x, d12w, е15v, f18u

There are two major tests of readiness for college: the act and the sat. act scores are reported on a scale from 1 to 36. the distribution of act scores in recent years has been roughly normal with mean µ = 20.9 and standard deviation s = 4.8. sat scores are reported on a scale from 400 to 1600. sat scores have been roughly normal with mean µ = 1026 and standard deviation s = 209. reports on a student's act or sat usually give the percentile as well as the actual score. the percentile is just the cumulative proportion stated as a percent: the percent of all scores that were lower than this one. tanya scores 1260 on the sat. what is her percentile (± 1)?