Every year, Mabel gets as many quarters as she is years old. She always puts these and nothing else in a piggy bank. When she turns 7, how much money is in the bank?
Thoughts? Step-by-step reasoning:
On her second birthday she adds $.5 because 2 x .25 = .5. On her third birthday she adds $.35 because 3 x .25 = .75. On her fourth birthday she adds $1 because 4 x .25 = 1. On her fifth birthday she adds $1.25 because 5 x .25 = 1.25. On her six birthday she adds $1.5 because 6 x .25 = 1.5. On her seventh birthday she adds $1.75 because 7 x .25 = 1.75. The total is $7 because .25 + .5 + .75 + 1 + 1.25 + 1.5 + 1.75 = 7.
Thus, the answer is 7.