Answer:
$3,384.31
Step-by-step explanation:
first of all we must determine how much money do you need to pay for 3 years of the facility:
PV = $100,000 x 2.6730 (PV annuity factor, 6%, 3 periods) = $267,300
if your mother does not invest more money, she will have $200,000 x (1 + 6%)⁴ = $252,495
this means that your mother will be $267,300 - $252,495 = $14,805 short
her annual contribution = $14,805 / 4.3746 (FV annuity factor, 6%, 4 periods) = $3,384.31