Andy has a number of friends who like dressing as zombies for Halloween. Two years ago, four of his friends dressed as zombies. Last year, that number increased by fifty percent. This year, the number increased by one third over last year. How many of Andy’s friends are dressing as zombies this year?
Two years ago: number of zombies = 4
Last year: 4 + 50% x 4 = 4 + 2 = 6
This year: 6 + (1/3) x 6 = 6 + 2 = ...