Answer:
With monthly compounding, the bank will calculate interest on your account just once per month. It will not update your balance on a daily basis when it calculates how much interest it owes you. Assuming that the APR is the same, accounts with monthly compounding offer a lower APY than accounts with daily compounding.
The sum of a geometric sequence is:
s(n)=a(1-r^n)/(1-r) in our case:
s(n)=3(1-4^n)/(1-4)
s(n)=-(1-4^n)
s(n)=(4^n)-1 and s=1023
(4^n)-1=1023
4^n=1024
n ln4=ln1024
n=(ln1024)/(ln4)
n=5
The answer is 21. 75²=5625 72²=5184 5625-5184=441 √441=21 so 21 is your answer. I hope this helps. The formula to figure out the hypotenuse A²+B²=C² can also be used to find a leg. Since we have one leg and the hypotenuse I was able to figure this out.