Most of the required information's are already given in the question. Using those information's the answer can be easily deduced.
Amount of water leaked by the faucet in 8 minutes = 668 milliliters
Then
Amount of water leaked by the faucet in 1 minute = (668/8) ml
= 83.5 ml
So we can see from the above deduction that the amount of water leaked by the faucet in 1 minute is 83.5 milliliters. There is nothing complicated about the problem except the calculation part. The division part of this problem has decimal number in the numerator and so care should be taken while dividing.