Kirk learned to play a total of 14 pieces over the course of 7 weeks of piano lessons. In all, how many weeks of piano lessons will Kirk need before he will be able to play a total of 26 pieces? Solve using unit rates.
To find the unit rate of learning pieces per week, we divide the total number of pieces learned by the number of weeks it took to learn them: $\frac{14 \text{ pieces}}{7 \text{ weeks}} = 2 \text{ pieces/week}.$ Since Kirk is learning pieces at a rate of 2 pieces/week, it will take $\frac{26 \text{ pieces}}{2 \text{ pieces/week}} = \boxed{13}$ weeks for him to be able to play a total of 26 pieces.
