Answer:
3
Explanation:
Inverse functions "undo" each other. f(g(3)) = 3, the number you start with.
To see this in the context of this problem...
g(3) = 3/5, f(g(3)) = f( 3/5 ) = 5(3/5) = 15/5 = 3.
g changes the input 3 to its output 3/5. f changes input 3/5 back to the original value 3
Real-life inverses: lock/unlock code a message/decode a message.