100 pts someone with my math don't do the graphs

Erik buys 2.5 pounds of cashews. if each pound of cashews costs $7.70, how much will he pay for the cashews?

7+(3n++8) what is the answer to this?

The water company charges a residential customer $41 for the first 3,000 gallons of water used and $1 for every 200 gallons used over 3000 gallons. if the water bill was $58 how many gallons of water were usedanswersa 3400 gallonsb 6000 gallonsc 6400 gallons d 7000 gallons