If 36 is 80% ( a piece) of a number. that means the number must be higher than 36
36 = 80% x n (n being the number) 36= .8n (changed the percent to a decimal by moving it back two places 36 = .8n .8 .8 I divided both sides by .8 - when you divide a number by a decimal (less than one) the number will become larger. The answer is 45 hope it helped :)
