what kind of soup needs milk? I don't know any...
anyway, the amount of the liquid at the end was 2 5/8 and milk was 1 1/3 - we need to substract the amount of milk from the amount of total liquid afterwards:
\(2 \frac{5}{8} -1 \frac{1}{3}\)
bring the fraction to the same form:
\(2 \frac{15}{24} -1 \frac{8}{24}\)
substracting:
\(1 \frac{7}{24}}\)
which is also the answer