\[\boxed{\mathbf{30.}}\]
\[3 + 57 + 1 = 60 + 1 = 61\]
\[62 - 2 - 1 = 60 - 1 = 59\]
\[30 + 41 - 10 = 71 - 10 = 61\]
\[50 - 13 + 10 = 37 + 10 = 47\]
\[1 + 39 - 7 = 40 - 7 = 33\]
\[85 - 10 + 15 = 75 + 15 = 90\]