An economy consists of 100 households. The first 30 households (group A) have $30,000 of income each in period 1, and $50,000 of income each in period 2. The second 70 households (group B) have $40,000 of income each in period 1, and $20,000 of income each in period 2. What is the present value of income from both periods from a household in group B?