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?.