Answer:
$160
Explanation:
In the monthly payment option she would pay $80 per month, therefore in a year (12 months) she would pay:
$80*12 = $960
We can see that this amount is greater than the $800 she would pay in the lump sum payment option.
The money she would save is:
$960 - $800 = $160
She would save $160 yearly with the lump sum payment option.