Question 18
(BUL 1) Find the highest degree $k$ of 1991 for which $1991^k$ divides the number
$$1990^{1991^{1992}}+1992^{1991^{1990}}.$$
$$1990^{1991^{1992}}+1992^{1991^{1990}}.$$
IMO 1991 - Shortlisted problems Question 18
IMO Shortlist · IMO 1991 - Shortlisted problems