Finance

I can't seem to get the right answer of $108,003.59 Problem: An oil well is expected to yield an annual net return of $25,000 for the next 15 years, after which it will run dry. An investor wants a return on his investment of 20%. He can establish a sinking fund earning 10% annually. How much should he pay for the oil well?

Finance

I need help trying to figure out which formula to use to get $10,078.44 Problem: Mr Jones wants to save for his son's college education. If he deposits $500 every 6 months at 6% compounded semiannually, how much will he have on hand at the end of 8 years?

Finance

John is the beneficiary of a trust fund set up for him by his grandmother. If the trust fund amounts to $20,000 earning 8% compounded semiannually and he is to receive the money in equal semiannual installments for the next 15 years, how much will he receive each 6 months?

Calculating the size of quarterly payments.

Bill borrows $1000 at 5% compounded annually. He is able to establish a sinking fund to pay off the debt and interest in 7 years. The sinking fund will earn 8% compounded quarterly. What should be the size of the quarterly payments into the fund?

Working with probability and combinations.

There are 5 rotten plums in a crate of 25 plums. How many samples of 4 of the 25 plums contain (a) Only good plums? (b) Three good plums amd 1 rotten plum? (c) One or more rotten plums?