mr martin has 36 calculators in a box. The ratio of the ordinary calculators to the scientific 5:1. How many of each calculator does he have

Fran would like to estimate the mean amount of time it takes people in her town to travel to work. the town's population is 150,000 and about 90,000 of those are working adults. which statements are true? select each correct answer. there is no way to infer the value of the mean. she must collect data for all 90,000 working adults and calculate the mean. a larger sample of working adults will provide a better estimate of the true mean than a smaller sample. the population of working adults is too large for using a sample to estimate the mean of the entire group. if she takes a random sample of the population of working adults in her town, the mean for that group is likely close to the mean for the entire group.

[10 points, algebra 2-simplifying complex fractions]according to my answer key the restrictions are -1 and 4. but why not positive 1?

What is the image of c for a 90° counterclockwise rotation about a? (3, 7) (-1, 3) (7, 3)