Zach uses a cookie-cutter approach to build identical tiny homes as part of his business, and this type of construction has a learning rate of 0.75. If it takes Zach 6.15 weeks to build the 10th tiny house, how long should it take him to build the 20th house, assuming there are no modifications to the houses along the way, in weeks?

5.27

61.5

10.14

4.61