Answer: The correct answer is choice C.
Step-by-step explanation: For the first three days there was 1/4 each day. One quarter equals .25, so .25 x 3 = .75.
On the fifth day the gauge decreased by 1/8. In order to determine the decimal equivalent of 1/8 we need to divide 1 by 8, which equals .125.
The equation to determine the amount of the water at the end of the week is .75 - .125, which equals .625. This is choice C.
