f(X) is the percent CORRECT on a test when there are 25 questions correct and x questions incorrect. What is the function? What is the percent correct on the test if there are 15 questions incorrect?
f(x) = [25/(25+x)]*100 If you think about it, when you calculate percentages of a test you always divide the score you got by the total score. For example, you have a test out of 100 points and you scored an 87. To get your percentage, you do 87/100 = 0.87 and then multiply by 100 to get a percentage of 87%. Same applies here. 25 correct divided by 25 correct + x incorrect all times 100. So, plug x = 15 into f(x). f(15) = [25/(25+15)]*100 = (25/40)*100 = 62.5% Good luck with your studies!