PS question

[zozo123]

In the first week of the year, Nancy saved $1. In each of the next 51 weeks, she saved $1 more than she had saved in the previous week. What was the total amount that Nancy saved during the 52 weeks?
A. $1,326
B. $1,352
C. $1,378
D. $2,652
E. $2,756


How can we find the sum of a list (1+2+3+4+...) ? thanks

[Cybermusings]

In the first week of the year, Nancy saved $1. In each of the next 51 weeks, she saved $1 more than she had saved in the previous week. What was the total amount that Nancy saved during the 52 weeks?
A. $1,326
B. $1,352
C. $1,378
D. $2,652
E. $2,756

In first week $1; in second week 2; in third week 3 hence in the 52nd week she would save $52
This is simple arithmetic progression; use the formula to find the sum of an arithmetic progression

{n [2a1 + (n-1)d]}/2
= {52[2 + (52-1)*1]}/2
= {52 [2+51]}/2
= 52*53 / 2
= 1378

[drhomler]

In the generic version of the formula what do a1 and d represent?

[Cybermusings]

a1 represents the first term of the sequence and d represents the difference between 2 consecutive terms

[drhomler]

Thank you that was very helpful. I appreciate it, and hopefully I get one like this on the exam.

[zozo123]

Cybermusings, thanks very much!!!