The answer is 8700. there you go sir or ma'm!
Just think of 8x10 it equals 80
Using the formula for slope, we can find out that
So -105 is the slope, and because she bought her laptop at $1160, the y-intercept is 1160. This means that the equation is V(t)=-105t+1160.
Imagine, at the first day you have only one penny. Then tomorrow you have 2 pennies, next day you have 4 (2x2), next day you have 8 (4x2), next day you have 16 (8x2).... and so forth.
It looks like geometric sequence isn't it? (the ratio between the number of pennies that you have from the 2nd day and the 1st day is 2)
So, by using geometric sequence theorem we can total those pennies until day-27
S (total pennies at day-27) = (1)(2^27-1) / 2-1 = 2^26 pennies
So, you have 2^26 pennies.. a big number of pennies huh?=))
{The formula is: S = a( r^n-1) / r-1
Where:
a= the number of pennies that you've got at the 1st day
n= number of days you spent to collect those pennies)
r= the ratio of the number of pennies}
