Yes, we need the sisters age to find it the answer, not trying to be rude we just need the sisters age.
The rate of interest is 25%
<u>Explanation:</u>
Given:
Principal, P = $2,000
Amount, A = $2500
Time, t = 1 year
Rate of Interest, r = ?
We know:

On substituting the value we get:


Therefore, the rate of interest is 25%
The answer should be
f=1/5 x^2 + -2/5x
You would do 5 times 4 which is 20. then count how many zero's there are and put them after the 20.