First, we count how far reached the Nell:
3,5 * 16 = 56 miles
Secondly, we count how far reached the Kristin:
3,5 * 18 = 63 miles
Now we expect the difference in the distance between them:
63 - 56 = 7 miles
The results that Kristin about seven miles driven more than Nell.
k = 12
cancel out the r on both sides
then divide -144 by -12.
you get 12.
Observe that as the series progresses, the term decreases by 1/4. To show this, observe the first four terms of the series below.
-200 = (1/4)(-800)
-50 = (1/4)(-200)
-12.5 = (1/4)(-50)
Since we have a common ratio, r, of 1/4, we can use the properties of a geometric series to find the 8th term of the series.
Recall that to find the sum of the nth term of a geometric series, we have

where a is the first term of the series and r is the ratio.
So, for the first eight terms, we have


Therefore, the sum of the 8th series is approximately -1066.65.
Answer: -1066.65