Bob and James Are Installing New Flooring in Their Home

Bob and James are installing new flooring in their home. The house has 5 rooms of approximately equal size where the flooring will be replaced. Bob and James spent 3 hours removing the old flooring from the first room. The average time to remove the flooring from 2 rooms is 2.25 hours per room. Determine the learning curve percentage experienced by Bob and James. Below are values that may be useful in answering this question. ln(95%) / ln(2) = -0.074
Ln(90%) / ln(2) = -0.152
Ln(85%) / ln(2) = -0.234
Ln(80%) / ln(2) = -0.322
Ln(75%) / ln(2) = -0.415
Ln(70%) / ln(2) = -0.515

A) 70%
B) 75%
C) 80%
D) Some other percentage