If a = the side of one small square and b = the side of the other small square and c = the side of the biggest square, then how could you write an equation using a, b, and c with exponents?

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