What is the reciprocal of 9/10 as a mixed number

What is the value of x in the diagram below?

One of the inventors of integrated circuits observed that the number of transistors that fit on an integrated circuit will double every 24 months. what type of relationship most appropriately models this situation?

Maria has $11 to buy fish for her aquarium. each goldfish costs $2. how many goldfish can she buy? do not include units in your answer