How can you tell if a number is divisible by 3?

a. the last number is 3. b. the sum of the digits of the number is a multiple of 3. c. the first two digits are divisible by 3. d. the number ends in an odd digit.

Suppose that 3% of all athletes are using the endurance-enhancing hormone epo (you should be able to simply compute the percentage of all athletes that are not using epo). for our purposes, a “positive” test result is one that indicates presence of epo in an athlete’s bloodstream. the probability of a positive result, given the presence of epo is .99. the probability of a negative result, when epo is not present, is .90. what is the probability that a randomly selected athlete tests positive for epo? 0.0297

Given ab and cb are tangents of p, and m =10°. what is the measure of abp?

When solving this problem: 3025/5.5 = a/90.75 you get 49912.5 which would be the length of one of the sides of a square when the area is only 90.75 inches. is that answer correct, why, and how is it possible?