What is / are the coefficients in this expressions? 3a+7-8n

Aswimming pool had 2.5 million liters of water in it. some water evaporated, and then the pool only had 22 million liters of water in it. what percent of the water evaporated?

You draw a card at random from a deck that contains 33 black cards and 77 red cards.

The diameter of a bacteria colony that doubles every hour is represented by the graph below. what is the diameter of the bacteria after 8 hours? graph of a curve passing through the points zero comma 1, one comma two, two comma four, and three comma eight