Hints: Problem 13.18 (14.18 in new text)
The old and new books use different salaries.
In the old edition, problem 13-18 uses $34k. In the new edition problem 14-18 uses $45k. Please use $45k on this problem just for consistency. Note that this is a GEOMETRIC GRADIENT problem, the equation for which is given on page 356 in the old book (388 in the new.)