Answer:
original number is 18.07
Step-by-step explanation:
Let the original number be x
x - 17% of x = 15
x* (1 - 0.17) = 15
x * 0.83 = 15
x = 15/0.83
x = 18.072289156
Or if your wording meant 17% of a number is 15 then:
x * 17% = 15
x *0.17 = 15
x = 15/0.17 = 88.23529...
but I think you meant "decreased by 17%" so I choose x = 18.07
