MAA MinuteMath: October 8, 2009

Thursday, October 8, 2009

October 8, 2009

Some boys and girls are having a car wash to raise money for a class trip to China. Initially 40% of the group are girls. Shortly thereafter two girls leave and two boys arrive, and then 30% of the group are girls. How many girls were initially in the group?

Interactive version of problem and solution.

Buy The Contest Problem Book VII

MAA MinuteMath

Exercise your mind daily with a problem from the AMC-8, AMC-10, or AMC-12, provided by Mathematical Association of America's American Mathematics Competitions.

Want more?

Curriculum Inspirations is a collection of resources for Middle and High School Math Teachers that demonstrate practical ways to engage students in the lively exploration of mathematics and mathematical thinking using problems from America’s longest-running and most successful mathematics competition. Developed by James Tanton, these resources include Ten Problem Solving Strategy Essays and Curriculum Bursts.

Contact MAA