Question

URGENT! Please show work!

A teacher is training for a half marathon in 2013. In one week she ran 5km on the first day and increased her distance by 10% on each subsequent day.
a) How far did she run on the seventh day?
b) What is the total distance she ran during the week?

Answer 1

Do you know compound interest?

Answer 2

I might need a refresher :(

Answer 3

the way i first tried solving this was with a geometric series formula. unless its different, im plugging everything in wrong...

Answer 4

currently i am using this formula
a of n=a of 1 times (r)^n-1

Answer 5

\[\sum_{n=0}^{7} 5*(1.1)^{n} = 5*(1.1)^{0} + 5*(1.1)^{1} +5*(1.1)^{2}....\]

Answer 6

n=6 is the seventh day in this set up, little confusing there sorry.

Answer 7

thats all right, the main thing im confused about is what formula I use to solve it?

Answer 8

i have specific term, finite sum, or infinite

Answer 9

and the total for the week is not
\[\sum_{n=0}^{7} \] but rather
\[\sum_{n=0}^{6}\]

Answer 10

alright, let me try that out

Answer 11

the answer to the problem is 8.86 for a and 47.44 for b btw

Answer 12

\[5*(1.1)^{6} = ?\]

Answer 13

8.86 :D

Answer 14

:)

Answer 15

thanks but if i dont mind asking how did you get 1.1 again?

Answer 16

i think i understand everything else

Answer 17

use this for the sum
\[a*(\frac{ 1-r^6 }{ 1-r })\]

Answer 18

where a=5 and r=1.1

Answer 19

oh alrighty

Answer 20

thank you so much, i really appreciate all the help!

Answer 21

sure:)