Justin is selling cans of soda. it costs him $3 each week to advertise his business. he buys each can for $0.30 and sells each one for $1.00. write an equation to model the amount of profit, p, justin makes from selling x cans of soda in one week. a. p = x − 3 b. p = 0.3x − 3 c. p = 3x + 0.7 d. p = 0.7x − 3