We try to find the number that 75% of it is 200 by set the number that we try to find by A -> A x 75/100 = 200 -> (A x 75)/100 = 200 -> A x 75 = 200 x 100 -> A x 75 = 20,000 ->A = 20,000/75 -> A = 266.6666... So that the number that 75% of it is 200 : 266.6667