Someone has some $1 and $5 bills in his pocket. he has a total of 15 bills worth $47. how many bills does he have

Which of these statements is correct? the system of linear equations 6x - 5y = 8 and 12x - 10y = 16 has no solution. the system of linear equations 7x + 2y = 6 and 14x + 4y = 16 has an infinite number of solutions. the system of linear equations 8x - 3y = 10 and 16x - 6y = 22 has no solution. the system of linear equations 9x + 6y = 14 and 18x + 12y = 26 has an infinite number of solutions.

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)?

Let f(x) = 1/x^2 (a) use the definition of the derivatve to find f'(x). (b) find the equation of the tangent line at x=2