A woman made 35,000 during her first year as a dog trainer. Each year she has recieved a 10% raise. Find the total earnings if this is her 8th year. (Use geometric sequence/Partial sum formula if you can)

Expert Answers

An illustration of the letter 'A' in a speech bubbles

The initial value a of the sequence is 35,000, the ratio is 1.1 since every year she receives the amount of the previous year plus 10%. The number of terms m is 8.

`a=35,000`

`r=1.1`

`m=8`

The sum of the first m members is equal to `(a(1-r^m))/(1-r)`

Substitute 35,000 for a 1.1 for r and 8 for m to determine the total earnings for the first 8 years.

`(35,000(1-1.1^8))/(1-1.1)`

`=(35,000(-1.1436))/(-0.1)`

`=400,256`

Thus she earned $400,255 after 8 years.

` ` To verify, write each term of the sequence and add them together:

n=1, 35,000

n=2, 35,000*1.1=38,500

n=3, 38,500*1.1=42,350

n=4, 42,350*1.1=46,585

n=5, 46,585*1.1=51,243.50

n=6, 51,243.50*1.1=56,367

n=7, 56,367*1.1=62,004.6

n=8, 62,004.6*1.1=68,205

The sum of all of them is 400,255

See eNotes Ad-Free

Start your 48-hour free trial to get access to more than 30,000 additional guides and more than 350,000 Homework Help questions answered by our experts.

Get 48 Hours Free Access
Approved by eNotes Editorial Team