If the first payment is at year 1, r = 10% and PV0 for this perpetuity is $80, what is the first payment? If the first payment is at year 2, r = 10% and PV0 for this perpetuity is $80, what is the first payment? If the first payment is at year 1, the first payment is $10 and PV0 for this perpetuity is $120, what is the interest rate