The length of a rectanglar sheetof paper is 3cm more than its breadth .The sheet of a paper has a perimeter of 42cm. what is its length

Can someone check if i did this correct. it’s number 4 if you’re wondering.

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

The function models the number of accidents per 50 million miles driven as a function