Let us follow the steps of this solution on Venn diagram.

At the beginning we draw a regular Venn diagram:

Then we should keep in mind denotations we use:

And start marking numbers we get from question statement:

*F* = 20

So

*R* =

*T* - 32

*N* = 0.2

*T**B* = 0.1

*T*So now we can construct an equation:

20 +

*T* – 32 + 0.2

*T* – 0.1

*T* =

*T**T* = 120