I think the answer is here Art of Problem Solving • View topic - fraction
1/x = 0.00N
1/y = 0.00P
the fraction 1/x and 1/y can be written as decimals as shown above , where N and P represent different digits . which of the following is equal to 1/xy if S equals N times P and S is a digit ?
a 0.0000S b 0.000S c 0.00S d 0.0S e 0.S