Jennifer 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?

A) $11

B) $11.50

C) $12

D) $12.50

We can translate the following statement into a1 equal to $11, n equal to 57, and s equal to $19799. The formula to be followed through derivation is

s = (n/2) * (a1 + a1 + d * (n-1)) $19799 = (57/2) * (2*11 + d*56) d = $12.01

The answer that is closest is option C

11*57+X (1+2+3 + ... + 56)

=11*57+X (1+56) * 56/2

=627+1596X

=19779

X = (19779-627) / 1596=12

Your answer is C