Question

ennifer has been saving for college for 57 months. The first month, she saved $11. She was able to save more money each month than the month before. She ended up saving $19,779.00. How much more did she save each month?

Answer 1

The is an arthitmetic sequence, so let's determined all the aspects and factors using the details and information from this word problem.
The first term (a) = 11, number of terms (n) = 57, the sum of nth term (Sn) = 19,779.
Let the common difference between the amount of money she saved more each month is d.
Sn = n/2(2a+(n-1)d)
19,799 = 57/2(2(11) + (57-1)d)
19,799 = 28.5(22 + 56d)
19,799 = 627 + 1,596d
    -627  -627
____________________
   19,172 = 1,596d
___________________
             1,596

d= 12.01253.

In conclusion, she saved about $12 more each month.