A number $x$ factors as $107\cdot109^5$, and $107$ and $109$ are primes. What is the exponent of $109$ in the prime factorization of $x^{11}$?

Last month, a 770 g box of cereal was sold at a grocery store for $3.10. however, this month, the cereal manufacturer launched the same cereal in a 640 g box, which is being sold at $2.50. what is the percent change in the unit price?