in the last test 40% of all students in Mrs. Well's class got grade A. How many students are studying in this class, if there were 28 A's on the test?

28 / x =.4

28 /.4 = x

x = 70 total students

Half of 40 percent is 20 percent so 20 percent is half of 28.28 divided 2 is 14. Now we know 20 percent is 14. Now what times 20 is 100. 20 x 5 is 100. Now because we multiplied 20 by 5 we multiply 14 by 5. So 70 students