Question 26
Consider the positive integer $n = 7 + 7^2 + 7^3 + \ldots + 7^{2017}$.
a) Show that the remainders of the divisions of $7^{2018}$ by $6$ and by $48$ are equal.
b) Determine the last two decimal digits of the number $6n$.
a) Show that the remainders of the divisions of $7^{2018}$ by $6$ and by $48$ are equal.
b) Determine the last two decimal digits of the number $6n$.