1. What volumes of fluids A and B should be mixed to obtain 150 units of a fluid C that contains 70 units of a substance, if A and B contain 50 and 80, respectively.

1a. Determine the unknowns.

1b. Give precise definitions of the unknowns.

1c. Translate the information in the problem description into mathematical statements.

1d. Use Maxima code to solve the problem above.