Answer:
The below is missing from the question:
Assume that they can earn 6% annual rate of return on their investment.
$4,853.48
Explanation:
The amount the couple should begin depositing can be determined using the pmt formula in excel as follows:
=-pmt(rate,nper,pv,fv)
rate is the 6% annual rate of return on their investment
nper is 18 years
pv is the present worth of the tuition fee which is unknown
fv is the amount of tuition required 18 years from now
=-pmt(6%,18,0,150000)
=$4,853.48