a. If $80,000 is invested at 30% and another $50,000 is invested at 20% per year, what is the overall rate of return on the entire $130,000?
b. A total of $100,000 was invested in two different projects identified as Z1 and Z2. If the overall rate of return on the $100,000 was 30% and the rate of return on the $30,000 invested in Z1 was 15%, what was the rate of return on Z2?