Someone please help quickly. If you were to randomly survey 20 people at 50 randomly chosen high schools, would this be a random sample? Why or why not?

Question 1(multiple choice worth 1 points)(07.06 mc)a group of students must collect at least $150 to organize a science fair. they have already collected $30. which graph best represents all remaining amounts of money, in dollars, that thestudents should still collect to organize the science fair? -210 -180 -150 - 120 -90-60 -300306090 120 150 180 210-210 -180 -150 - 120 -90 -60 -30 0 30 60 90 120 150 180 210-210 -180-150 - 120 -90-60-300 30 60 90 120 150 180 210-210 -180 -150 - 120.90 -60 -30 0 30 60 90 120 150 180 210

The number of chocolate chips in an 18-ounce bag of chocolate chip cookies is approximately normally distributed with a mean of 1252 chips and standard deviation 129 chips. (a) what is the probability that a randomly selected bag contains between 1100 and 1500 chocolate chips, inclusive? (b) what is the probability that a randomly selected bag contains fewer than 1125 chocolate chips? (c) what proportion of bags contains more than 1225 chocolate chips? (d) what is the percentile rank of a bag that contains 1425 chocolate chips?

Whats are the trickiest steps to do when adding or subtracting rational expressions? how does knowledge of rational numbers u in adding and subtracting rational expressions?