so.. whatever "x" is, we know 1125 + x = y
and whatever the alcohol concentration yield may be, we know
(1125)(0.9) = 0.75y
(1125)(0.9) = 0.75y <--- solve for "y", that's how much the final amount of milliliters will be
how much pure water was added? subtract 1125 from that, or y - 1125
