Question

In March, a family starts saving for a vacation they are planning for the end of August. The family expects the vacation to cost $1375. The start with $125. Each month they plan to deposit 20% more than the previous month. Will they have enough money for their trip? If not, how much more do they need?

Answer 1

@iGreen

Answer 2

they have enough money for their trip

Answer 3

Please don't give me a direct answer... that doesn't help, and it's against the rules.

Answer 4

Do you know the process for solving this problem?

Answer 5

125 + 20% * 5

Answer 6

I'm pretty sure I need to use the summation notation of some sort

Answer 7

and wouldn't it be 120%? 20% would decrease the value... that makes no sense.

Answer 8

Don't I need to use \[S _{n}=\frac{ a _{1}(1-r ^{n}) }{ 1-r }\]

Answer 9

@CountryGurl15

Answer 10

Um, yes you are on the right track =) I thought your problem said 20% tho =)

Answer 11

So would \[a_1=125\] \[n=5\] and \[r=1.2\] ?

Answer 12

Yes that looks right =)

Answer 13

So solve now, and see what you get =)

Answer 14

\[S_5=\frac{ 125(1-1.2^5) }{ 1-1.2 }\]

Answer 15

Yup, now u hafta just solve

Answer 16

Sorry! my openstudy was glitchy. so we have\[S_5=\frac{ 125(1-2.48832) }{1-1.2 }\]
\[=\frac{ 125(-1.48832) }{ -0.2}\]
\[=\frac{ -186.04 }{ -0.2 }\]
\[=930.20\]

Answer 17

So they don't have enough money?..

Answer 18

@CountryGurl15

Answer 19

Um, no they don't apparently =)

Answer 20

Okay.... is that correct?

Answer 21

Thanks for your help.

Answer 22

Yes that is correct, and No problem =)