Mrs. beach bought shells at a gift shop. the red shells (r) were $0.75 each, and the white shells (w) were $0.49 each. the total cost was $4.70 for 8 shells. later, the clerk forgot how many of each color shell he sold, so he guessed 4 red and 4 white shells. that was 8 shells, but the cost was $4.96. what advice would you give the clerk for his next guess?