What is the output explain with reason

Question

def Foo(n):
def multiplier(x):
return x*n
return multiplier

a = Foo(4)
b = Foo(4)
print(a(b(5)))

Answer 1

The function Foo returns the function multiplier which is assigned to a. Now for example if you say a(5), it will go to the function Foo and inside it will execute the multiplier function with a value 5. Since n was 4 already, it would return 5*4=20.

In your case b(5) is 20 like explained above and then a(20) will give 4*20=80.