We have a random variable X that is the number of months that a certain owner of an estate needs to pay a loan in the Bank if he/she has a contract with insurance company to help him/her to pay a loan. X's probability mass function is:
$$f(x)=\frac{5-x}{10}, x= 1,2,3,4$$
If the owner receives 200usd from the insurance comp per month for the first 2 months and then 100usd per month after the first 2, what is the expected payment for the loan at the bank?
For this question, I'm having a hard time understanding where I would plug in the 200usd and 100usd, I assume the formula for expected value would be used here but it still does not help me know where to place the amount... Perhaps $$E(X)=\sum xf(x)= 200*x_1*f(x_1) + 200*x_2*f(x_2) + 100*x_3*f(x_3) + 100*x_4*f(x_4) $$??
If I could get a hint for this that would be great!
Thank you