just need help on B! Got A correct but B is coming up wrong. Thank you!

Carla Vista Inc. wants to purchase a new machine for $37,840, excluding $1,400 of installation costs. The old machine was purchased 5 years ago and had an expected economic life of 10 years with no salvage value. The old machine has a book value of $2,200, and Carla Vista Inc. expects to sell it for that amount. The new machine will decrease operating costs by $8,000 each year of its economic life. The straight-line depreciation method will be used for the new machine for a b-year period with no salvage value. Click here to view the factor table. (a) Determine the cash payback period. (Round cash payback period to 2 decimal places, eg. 10.53.) Cash payback period years Determine the approximate internal rate of return. (Round answer to 0 decimal places, eg. 13\%. For calculation purposes, use 5 decimal places as displayed in the factor table provided.) Internal rate of return %