6. (a) A man has $4.55 in change composed entirely of dimes and quarters. What are the maximum and minimum number of coins that he can have? Is it possible for the number of dimes to equal the number of quarters? (b) The neighborhood theater charges $1.80 for adult admissions and $.75 for children. On a particular evening the total receipts were $90. Assuming that more adults than children were present, how many people attended? (c) A certain number of sixes and nines is added to give a sum of 126; if the number of sixes and nines is interchanged, the new sum is 114. How many of each were there originally?