a

Monthly payment (P)= 985.47

remaining years after 4 years = 15-4 =11

remaining months (n)=11*12 =132

interest rate per month (i)=3.8%/12=0.003166666667

Unpaid balance formula (PV)=P *(1-(1/(1+i)^n))/i

985.47*(1-(1/(1+0.003166666667)^132))/0.003166666667

=106182.6766

So loan balance after 4 years is $106182.68

b

Monthly payment (P)= 985.47

remaining years after 5 years = 15-5=10

remaining months (n)=10*12 =120

interest rate per month (i)=3.8%/12=0.003166666667

Unpaid balance formula (PV)=P *(1-(1/(1+i)^n))/i

985.47*(1-(1/(1+0.003166666667)^120))/0.003166666667

=$98,254.85

So loan balance after 5 years is $98,254.85

c

Total payment made in year 5 = monthly payment * number of month in year

=985.47*12

=$11,825.64

So We paid $11,825.64 to bank in year 5

d

Amount applied to principal = loan balance after 4 years - loan balance after 5 years

=106182.68-98254.85

=$7,927.83

So amount applied to principal during 5th year is $7,927.83

e

interest paid in 5th year = Total payment made - payment made towards principal

=11825.64-7927.83

=$3,897.81

So interest paid in 5th year is $3,897.81