Please help me im so confused

Asequence is defined recursively using the formula f(n + 1) =f(n) - 5. which sequence could be

Onnie is considering doing some long term investing with money that she inherited. she would like to have $50,000 at the end of 30 years. approximately how much money would lonnie need to put into an account earning 6% interest compounded annually in order to meet her goal?

Betty correctly answers 30 questions on your math test there are 40 questions on the test what percent of the questions did she answered incorrectly