A number is first decreased by 10% and then increased by 10%. The number so obtained is 50 less than the original number. The original number is :

Answer: Option B

Let the original number = x
According to the question,
x × $$\frac{90}{110}$$ × $$\frac{110}{100}$$ = (x - 50)
x × $$\frac{99}{100}$$ = x - 50
99x = 100x - 5000
x = 5000
Hence original number = 5000