let the amount invested be P
let the rate be i
900 must be the difference in the balance between year n and year n+1, and the same for the following year:
p(1+i)^(n+1) - p(1+i)^n = 900
p(1+i)^(n+2) - p^(n+1)^(n+1) = 981
from first: p(1+i)^n[(1+i - 1) = 900
from 2nd: p(1+i)^n[ (1+i)2 - (1+i)] = 981
divide them:
i/(1 + 2i + i^2 -1 - i) = 100/109
100i^2 + 100i = 109i
100i^2 -9i = 0
i(100i - 9) = 0
i = 0 , not likely or i = 9/100 = .09 or 9%
so what amount would yield $900 at 9% ?
= 900/.09 = $10,000
I believe I was overthinking that question.
#2
suppose we have an n-gon
sum of interior angles = 180(n-2)
sum of all the exterior angles of any n-gon = 360°
so
180(n-2) = 360
n-2 = 2
n = 4
must be a quadrilateral
A sum is invested at compound interest payable annually. The interest in two successive years was Rs 900 and Rs 981. Find the sum.
If the sum of all internal angles and sum of all external angles of a regular polygon are equal, then the number of sides of the polygon is?
Pls help***
1 answer