Two sociologists have grant money to study school busing in a particular city. They wish to conduct an opinion survey using 691telephone contacts and 471house contacts.

 Two sociologists have grant money to study school busing in a particular city. They wish to conduct an opinion survey using 691telephone contacts and 471house contacts. Survey company A has personnel to do 37 telephone and 13 house contacts per​ hour; survey company B can handle 28 telephone and 20
 house contacts per hour. How many hours should be scheduled for each firm to produce exactly the number of contacts​ needed?