请教各位牛牛，给我个思路，谢谢
1.At least 100 students at a certain high school study Japanese. If 4 percent of the students at the school who study French also study Japanese, do more students at the school study French than Japanese? (1) 16 students at the school study both French and Japanese. (2) 10 percent of the students at the school who study Japanese also study French. answer:B 2.In the xy-plane, does the line with equation y = 3x + 2 contain the point (r, s) ? (1) (3r + 2 - s)(4r + 9 - s) = 0
(2) (4r - 6 - s)(3r + 2 - s) = 0 answer:C 3.A vending machine is designed to dispense 8 ounces of coffee into a cup. After a test that recorded the number of ounces of coffee in each of 1,000 cups dispensed by the vending machine, the 12 listed amounts, in ounces, were selected from the data. If the 1,000 recorded amounts have a mean of 8.1 ounces and a standard deviation of 0.3 ounce, how many of the 12 listed amounts are within 1.5 standard deviations of the mean? (A) Four (B) Six (C) Nine (D) Ten (E) Eleven answer:E 4.The rate of a certain chemical reaction is directly proportional to the square of the concentration of chemical A present and inversely proportional to the concentration of chemical B present. If the concentration of chemical B is increased by 100 percent, which of the following is closest to the percent change in the concentration of chemical A required to keep the reaction rate unchanged?
(A) 100% decrease (B) 50% decrease (C) 40% decrease (D) 40% increase (E) 50% increase answer 5.If n is a positive integer and n2 is devisible by 72 then the largest positive integer that must divide n is=? answer:12 | 
