Answer: $24,747.92
Based on the given amounts of increased in savings for the first 3 months, we have the following assumptions:
1) That the savings increase by 2.44% monthly
$18,962.50 -18,500=462.50, 462.50/18962*100=2.44%
$19,436.56--$18,962.50=$474.06, 474.06/19,436.56*100=2.44%
$19,922.48-$19,436.56=485.92, 485.92/19,922.48*100=2.44%
2) That the monthly interest for the first 3 months had an incremental of $0.30 monthly
462.50,474.06 and 485.92 has an incremental of 11.56 and 11.86 (with a difference of .30)
Continuing on with the increments gives savings of $24,747.92 in the 12th month.