Im really confused on this one

Trish receives $450 on the first of each month. josh receives $450 on the last day of each month. both trish and josh will receive payments for next four years. at a discount rate of 9.5 percent, what is the difference in the present value of these two sets of payments?

Which term best describes the association between variables a and b

Is it greater than or less than7*3_9*2