Yo can someone help me out

Ijust need to see how to do this. so you don’t have to answer all of them just a step by step explanation of one.

Suppose that a households monthly water bill (in dollars) is a linear function of the amount of water the household uses (in hundreds of cubic feet, hcf). when graphed, the function gives a line with slope of 1.65. if the monthly cost for 13 hcf is $46.10 what is the monthly cost for 19 hcf?

Bo is buying a board game that usually costs bb dollars. the game is on sale, and the price has been reduced by 18\%18%. what could you find the answer?