Richland's real GDP per person is $10,000, and Poorland's real GDP per person is $5,000. However, Richland's

Question:

Richland's real GDP per person is $10,000, and Poorland's real GDP per person is $5,000. However, Richland's real GDP per person is growing at 1 percent per year and Poorland's is growing at 3 percent per year. Compare real GDP per person in the two countries after 10 years and after 20 years. Approximately how many years will it take Poorland to catch up to Richland?