Answer:
You need to have in mind that you are looking at the present value because the lump sum is worth $50,000 today. You need to compare the present for 10 years of your life would be worth today.
So:
FV=0
N=10 X 12=120
PMT= 641
I=6.5% / 12= 0.5417%
Solve for PV= $56,451.91 (is larger than $50,000)