Levi just started a running plan where he runs 8 miles the first week and then
increases the number of miles he runs by 5% each week. If he keeps up this plan for
19 weeks, how many total miles would Levi have run, to the nearest whole number?

Respuesta :

Answer:

244 miles (nearest whole number)

Step-by-step explanation:

We can model this as a geometric series.

General form of a geometric sequence: [tex]a_n=ar^{n-1}[/tex]

(where a is the first term and r is the common difference)

Given information:

  • Miles run in first week = 8
  • Weekly increase of miles = 5%
  • Total number of weeks in plan = 19

Therefore:

  • [tex]a[/tex] = 8
  • [tex]r[/tex] = 1.05
  • [tex]n[/tex] = 19

Sum of the first n terms of a geometric series:

[tex]S_n=\dfrac{a(1-r^n)}{1-r}[/tex]

Therefore, sum of the first 19 terms:

[tex]\implies S_{19}=\dfrac{8(1-1.05^{19})}{1-1.05}[/tex]

[tex]\implies S_{19}=244.3120313...[/tex]

So Levi ran a total of 244 miles (to the nearest whole number)