The structural engineering design section within the engineering department of a regional electrical utility corporation has developed several standard designs for a group of similar transmission line towers. The detailed design for each tower is based on one of the standard designs. A transmission line project involving 50 towers has been approved. The estimated number of engineering hours needed to accomplish the 8 th and 50th tower are 108 hours and 94.3 hours respectively. Determine the learning curve percentage and estimate of the number of engineering hours needed to design the 10th tower in the project