Answer:
Interest paid each year = 5% of 1000 = $50
$1000 is to be paid at the end of 10 years.So payment each year = pmt(rate,nper,pv,fv) where rate = 0.04,nper=10 and fv =1000.
Payment into the fund =pmt(0.04,10,0,1000) = $83.29 each year
Value of the sinking fund at the end of the 4th year =pv(rate,nper.pmt) =pv(0.04,4,83.29) = 302.34
Interest earned by sinking fund in year 5 = 0.04*302.34 = 12.09
Interest on loan in 5th year = $50
So difference between the interest payment on the loan and the interest earned by the sinking fund in the fifth year. = 50-12.09 = 37.91 = $38 (to nearest whole number)