On a trip, the fare was 50¢ for each adult and 25¢ for each child. if 30 passengers paid $12.25, how many adults and children went?
which of the following equations could not be used to solve the problem?

a. 50x + 25(30 - x) = 1225
b. 50(30 - x) + 25x = 1225
c. 25x + 50x = 30(1225)

Refer to interactive solution 17.45 to review a method by which this problem can be solved. the fundamental frequencies of two air columns are the same. column a is open at both ends, while column b is open at only one end. the length of column a is 0.504 m. what is the length of column b?

Acoin bank containing only dimes and quarters has 12 more dimes than quarters. the total value of the coins is $11. how many quarters and dimes are in the coin bank?

Write an inequality and solve each problem. for exercises 11 and 12, interpret the solution.