A college student is looking at her monthly checking account records. On September 1, 2008, her checking account held a balance of $1,050. At the end of March 2009, her checking account held a balance of $800. What is the monthly rate of change for the student’s checking account over the period September 1, 2008 through March 31, 2009?

help please

Question

A college student is looking at her monthly checking account records. On September 1, 2008, her checking account held a balance of $1,050. At the end of March 2009, her checking account held a balance of $800. What is the monthly rate of change for the student’s checking account over the period September 1, 2008 through March 31, 2009?

help please

anonymous · Answer

$250

anonymous · Answer

i thought so . thanks

anonymous · Answer

wait no thats wrong ...

jack1 · Answer

monthly charge
1st: how many months between Sept 1 2008 and March 31 2009?

anonymous · Answer

6

jack1 · Answer

yeah, but 7 including sept and march

jack1 · Answer

sept
oct
nov
dec
jan 
feb
mar

jack1 · Answer

so initial balance was 1050
and final balance was 800
so amount lost is??

anonymous · Answer

oh okay

jack1 · Answer

all good ;)

anonymous · Answer

but when i answered that it said i was wrong

jack1 · Answer

yep, but it wants the answer as a monthly amount
so $250 total lost in 7 months
= 250/7 per month
= about $35.71/month

jack1 · Answer

is that what you got before?

anonymous · Answer

yes

jack1 · Answer

ok, so the answer isn't linear then
35.71 is based on a fixed rate of change per month
so lets try a % based answer

jack1 · Answer

so A = P (1+rt)
Amount (A) = Principal (P) (   1 + Rate(r) x Time (t) )
have u used this formula before?

jack1 · Answer

800 = 1050 (1 + 7r)
800/1050 = (1 + 7r)
r = -0.034 per month
as a percentage = -3.4% per month

anonymous · Answer

no i havent. but nevermind. thank you though, i appreciate your kindness ...

jack1 · Answer

k
sorry