Answer:
1.5
Explanation:
As it is evident in the question that a slice of pepperoni pizza costs £1 in London and $2 in the US.
The real exchange rate will be 'r' , 3 times of a slice of British pizza for one slice of the American pizza.
r = Nominal exchange rate * (Price in US/Price in London)
3 = Nominal exchange rate * (2/1)
Nominal exchange rate = £1.5.
I hope this answer helps you out.
Thank You and Good luck.