280
30 + (50 x 5) = 280
*Order of operations. Without specifying parentheses, multiplication occurs before addition or subtraction.
This depends on the assumption that the symbol for double axes represents an axe x 2, and therefore a single axe = 5
An equally defensible position is that the crossed double axes is a single axe 'squared', so an axe squared = 10, and one axe = square root of 10 or 3.16.....
The solution then becomes
30 + (50 x 3.16) = 188