1) We receive $3,000 per semester and $87,000 in 9 years from the present.

What ROR did we attain, if we now invest $4,000?

(So I think this means we revive 3,000 twice a year for 9 years with a lump sum of 87,000 in the 9th year. but I am not sure how to calculate rate of return and what to do with the 4,000 invested amount) Please show formulas and steps

2) We buy an asset for $20,000. We receive money to the tune of ___ per month.

At the end, 4 years later, we are paid $12,000. The ROR is 10%. What was that money receipt?