74. Sally has twice as many sisters as she has brothers. Her brother Patrick has five more sisters than he has brothers. What is the least number of girls and boys in the immediate family that fits the above configuration?
78. In a contest to guess the number of balloons in a bunch, Alice guessed 31, Betty guessed 29, Carol guessed 23, Denise guessed 25, and Edith guessed 27. Two were wrong by 2, and two were wrong by 4. The other was correct. How many balloons were there and who guessed right?
79. Charley bought a motorcycle to tour the country with. After two years, it had depreciated to $6,000 and in five years it had a book value of $3,750. What did the motorcycle cost originally, and how long before it would have a book value of $0?
80. My wife and I can't seem to get our watches to work properly. Hers consistently runs one minute per hour fast, and mine runs two minutes per hour slow. This morning we nearly missed a wedding because our watches were an hour apart and we looked at the slower one. How many hours had elapsed since we set both of them properly?