SOLUTION: please help me with this question.. At the beginning of the day,the prices of stocks A and B are the same.At the end of the day,the price of stock A has increased by 1/10 of its o

Algebra ->  Numeric Fractions Calculators, Lesson and Practice -> SOLUTION: please help me with this question.. At the beginning of the day,the prices of stocks A and B are the same.At the end of the day,the price of stock A has increased by 1/10 of its o      Log On


   



Question 933366: please help me with this question..
At the beginning of the day,the prices of stocks A and B are the same.At the end of the day,the price of stock A has increased by 1/10 of its original price and the price of stock B has decreased by 1/10 of its original price .The new price of stock A is what fraction of the new price of stock B?

Answer by KMST(5328) About Me  (Show Source):
You can put this solution on YOUR website!
At the beginning of the day, both stocks have a price of 10 in some currency.
(If there is no currency that will do that, I can invent one).
At the end of the day, the price of stock A is
10%2B%281%2F10%29%2A10=10%2B1=11 ,
while the rice of stock B is
10-%281%2F10%29%2A10=10-1=9 ,
so the new price of stock A, as a fraction of the new price of stock B, is
highlight%2811%2F9=1%262%2F9%29

NOTE:
Solved as shown above, you can easily get to the answer,
which is a great advantage for timed tests where you do not need to "show your work".
If you need to show your work, and/or
if your teacher objects to the use of made-up currencies,
you can do the same calculations starting with
"Let x be the price of either stock at the beginning of the day."
Then, the new price of stock A at the end of the day is
x%2B%281%2F10%29%2Ax=x%2B0.1x=1.1x ,
and the new price of stock B at the end of the day is
x-%281%2F10%29%2Ax=x-0.1x=0.9x ,
so the new price of stock A, as a fraction of the new price of stock B, is
1.1x%2F%220.9+x%22=1.1%2F0.9=highlight%2811%2F9=1%262%2F9%29