4. Michael Howittt of Berkly, Michigan, recently had his gallbladder removed. His total bill for this surgery, which was his only health care expense for the year, came to $13,890. His healthcare insurance plan has a $500 annual deductible and an 80/20 coinsurance provision. The cap on Michael's coinsurance share is $2,000.

a.) How much of the bill will Michael pay?

b.) How much of the bill will be paid by Michael's insurance?