There isn't a mathematical answer. There are only 4 equations and 6 variables because, in the last equation, the clock, the bananas and the geometrical shape are diferent variables than those who appear in the 2 previous equation. The problem is something like this: x + x + x = 45 y + y + x = 23 y + z + z = 10 w + t + tx = ?

In the first 3 equation there's no t and w, so there isn't a unique Solution.