SOLUTION: hi i started a table but could not see a stock price of 30 or 31? can you please help Abercrombie and Fitch stock had a price given as P = 0.2t2 − 5.6t + 50.2, where t is t

Algebra ->  Quadratic Equations and Parabolas  -> Quadratic Equations Lessons -> SOLUTION: hi i started a table but could not see a stock price of 30 or 31? can you please help Abercrombie and Fitch stock had a price given as P = 0.2t2 − 5.6t + 50.2, where t is t      Log On


   

Question 1153501: hi
i started a table but could not see a stock price of 30 or 31? can you please help
Abercrombie and Fitch stock had a price given as P = 0.2t2 − 5.6t + 50.2, where t is the time in months from 1999 to 2001. (t = 1 is January 1999). Use MS-Excel to find the two months in which the price of the stock was $31 or $30.
thanks
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Found 2 solutions by greenestamps, MathLover1:
Answer by greenestamps(13198) About Me  (Show Source):
You can put this solution on YOUR website!


There are 2 months when the price was $31; there are none when the price was $30.

I can't know why you didn't find them, because I don't know what you did to try to find them....

Re-post showing or describing what you TRIED to do to work the problem....

Answer by MathLover1(20849) About Me  (Show Source):
You can put this solution on YOUR website!

Abercrombie and Fitch stock had a price given as
P+=+0.2t%5E2+-5.6t+%2B+50.2
where t is the time in months from 1999 to 2001. (t+=+1 is January 1999).
Use MS-Excel to find the two months in which the price of the stock was $31 or $30.
P+=+0.2t%5E2+-5.6t+%2B+50.2 if $P=31
31=+0.2t%5E2+-5.6t+%2B+50.2
+0.2t%5E2+-5.6t+%2B+50.2-31=0
+0.2t%5E2+-5.6t+%2B+19.2=0...factor
+0.2%28t%5E2+-28t+%2B+96%29=0
+0.2%28t%5E2+-24t-4t+%2B+96%29=0
+0.2%28%28t%5E2+-24t%29-%284t+-+96%29%29=0
+0.2%28t%28t+-24%29-4%28t+-+24%29%29=0
0.2+%28t+-+24%29+%28t+-+4%29+=+0
solutions:
if %28t+-+24%29++=+0->t=24
if +%28t+-+4%29+=+0->t=4
the two months in which the price of the stock was $31, t+=+1 is January 1999:
t+=+4 is April 1999
t+=+24 is January 2001

P+=+0.2t%5E2+-5.6t+%2B+50.2 if $P=30
30=+0.2t%5E2+-5.6t+%2B+50.2
+0.2t%5E2+-5.6t+%2B+50.2-30=0
+0.2t%5E2+-5.6t+%2B+20.2=0...use quadratic formula
+t=%28-b%2B-sqrt%28b%5E2-4ac%29%29%2F2a......a=0.2,b=-5.6,c=20.2
+t=%28-%28-5.6%29%2B-sqrt%28%28-5.6%29%5E2-4%2A0.2%2A20.2%29%29%2F%282%2A0.2%29
+t=%285.6%2B-sqrt%2831.36-16.16%29%29%2F0.4
+t=%285.6%2B-sqrt%2815.2%29%29%2F0.4
+t=%285.6%2B-3.9%29%2F0.4
solutions:
+t=%285.6%2B3.9%29%2F0.4=>+t=23.75-> not full month
+t=%285.6-3.9%29%2F0.4=>+t=4.25-> not full month
the two months in which the price of the stock was $30: none