Let the unknown number be x.
5/11 * x = 55
Since x is being multiplied by 5/11, and you want x alone, you need to multiply both sides of the equation by the reciprocal of 5/11 which 11/5.
11/5 * 5/11 * x = 55/1 * 11/5
x = 605/5
x = 121
Answer: The number is 121.
