8/(1/6) = (8/1)/(1/6) = (8/1) * (6/1) = 48/1 = 48
Patel found the quotient incorrectly since he got 1/48.
To check the division, he needed to multiply 48 by 1/6 and get 8.
Instead, he multiplied 1/48 by 6, so the multiplication done as a check is also incorrect.
Answer: last choice