For a positive integer n, if the difference between all neighbouring digits are all greater than 3 (e. g. 150), it is defined as a “good number”. How many three-digit “good number(s)” is/are there?

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.

Problem fathi wants to print out a pdf document that is 48 pages long. to save paper, he decides to print on both sides of each sheet and to print two pages on each side of the sheet. how many sheets of paper will he need?

Two cars which are 40 miles apart start moving simultaneously in the same direction with constant speeds. if the speed of the car which is behind is 56 mph and the speed of the other car is 48 mph, how many hours will it take for the car which is behind to catch up the car ahead of it?