Question

Phillip received 75 points on a project for school. He can make changes and receive two-tenths of the missing points back. He can make corrections as many times as he wants. Create the formula for the sum of this geometric series and explain your steps in solving for the maximum grade Phillip can receive. Identify this as converging or diverging

Answer 1

@ganeshie8 @zepdrix

Answer 2

PLEASE HELP D:

Answer 3

evidently he has 25 more points to go right?

Answer 4

yes

Answer 5

but how do i make the formula

Answer 6

so he can have \(75+25\times \frac{2}{10}\)

Answer 7

btw does it really say \(\frac{2}{10}\) ?

Answer 8

@IMStuck

Answer 9

yes it does

Answer 10

cant you simplify \[\frac{ 2 }{ 10 }\] into \[\frac{ 1 }{ 5 }\]?

Answer 11

ok on planet earth we usually call that \(\frac{1}{5}\) and you can add up
the first time he gets
\(25\times \frac{1}{5}=5\) the second time
yes of course

Answer 12

now he has \(80\) points leaving \(20\)
hmmm this is not as simple as i thought, but i bet we can still do it

Answer 13

So what is the formula then? just 75=25 x 1/5?

Answer 14

75+25*

Answer 15

the geometric sequence meant to be ar^n-1
u will have 75,80,84 this is the grades
the the increasing is
5,4,3.2,2.56
ar^n-1
a= 5
r = 4/5.

Answer 16

the next time he can get
\(20\times \frac{1}{5}=4\) and now he has \(84\) points leaving \(16\)
the increase each time is
\(25(\frac{1}{5})^n\)

Answer 17

what @Catch.me said

Answer 18

and the formula for the sum is
\[a(\frac{ 1-r ^{n} }{ 1-r })\]
so make that = 25 (the maximum )
\[25= 5(\frac{ 1-(\frac{ 4 }{ 5 })^{n} }{ 1-\frac{ 4 }{ 5 } })\]

Answer 19

n goes to infinity.

Answer 20

http://openstudy.com/study#/updates/526ebcb0e4b0c0f84759f7bc
@ceol1998 are you with me or i got it wrong??

Answer 21

i got it right :) thanks

Answer 22

you are welcome, can you explain to me what converging or diverging mean??