LEVEL 10 William and Ben are neighbors and found out they are born on the same day of the year.
William is 4 times older than Ben. But when you add their ages together and subtract 8 the
answer is 67. How old is Ben?
( you must create equations and solve by substitution to receive credit)

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

Find all solutions for 2y - 4x =2 y = 2x + 1 site: socratic.org

21 a stick 7 inches long is broken into two pieces, so that one piece is twice as long as the other one. how long are the two pieces?