Sophia is planning the graduation banquet. The caterer charges a fixed amount plus an additional charge for each person who attends. The banquets will cost $ 11 250 if 600 people attend $ 7650 if 400 people attend. (a) Suppose 340 people attend the banquet. What will the total cost be? (b)The total cost was $9810.How many people attended the banquets? (c)What strategies did you use to answer parts a and b?