Hello there! Just by looking at the choices, C is definitely out, because 9/10 is equivalent to 90%, not 45%. Looking at answer choice A, that number equals 4.5%, because 0.045 * 100 is 4.5%. In this case, A is also eliminated. 0.45 is equivalent to 45%, because 0.45 * 100 is 45%. B works. D also works, because 9/20 is 0.45, and once again, 0.45 * 100 is 45%. 0.45 and 9/20 are equivalent to 45%. The answers are B and D.
