20 is 40% of What Number? 20 is 40% of What Number? – 20 is 40(percent)% ofÂ 50. 100(percent)% of 50 is 50, therefore 40 percent(%) of 50 equals(=) 20. let’s learn how to get 20 is 40 percent of what number, see the step-by-step instructions below. 20 is 40 Percent of What Number? 50