Please infer what the number represented by the question mark below is.

The number of question marks in the middle is generally the number of conversion results of four groups of numbers.

For example, if any straight line around corresponds to 2 numbers, you can add, subtract, multiply and divide the result and put it in the middle.

There is an obvious number in the middle of the Ferris wheel: "60", which means the product of straight lines = "60".

And we have to add up all the numbers around us to be "75". This number should be in the middle of the Ferris wheel. The question mark is the most correct and can represent an indisputable number.