Question

You decide to save money to pay the fees for your hobby classes and save $22 in the first week. If you save $3 more each week than in the preceding week, how much money will you have by the end of the 10th week?

A.) $340
B.) $355
C.) $381
D.) $407
E.) $435

Answer 1

The situation described above forms an arithmetic series with first term (a1) equal to 22 and common difference (d) equal to 3. The sum of the first 10 terms is calculated by,
Sn = (n/2) x (2a1 + (n - 1) x d))
Substituting,
S10 = (10/2) x (2 x 22 + (10 - 1) x 3))
The value is 355. Therefore, the answer is letter "B. $355"