You earned a 90% on a science test. You answered 18 questions correctly. How many questions were on the test?

There were twenty questions on the test, we can figure this out by writing your word problem as an equation: x= the amount of questions there are on the test, with this in mind the equation will be written out 18/x=90%, then do the same to both sides of the equation, divide both sides by .90 which gets rid of the x on the left side and 18 divided by .90 = 20. So X = 20.