How wwas this capital stock per effective worker were derived, please explain the formula, just take it and try even a little

Here, the right-hand side is approximately 1 + 7 - p. Therefore, the real interest rate in the steady state must be approximately equal to the subjective discount rate plus the growth of production per worker: rep+ 8. This equation determines the long-run real interest rate in a growing economy. An economy with high growth should have a high real interest rate. Why is this? The reason can be found in the theory of consumption. In a growing economy, consumers expect to have higher income in the future than today. If the real inter- est rate were equal to the subjective discount rate, consumers would prefer to consume the same amount in every period. In a growing economy, this would mean that they would take loans based on their expected future incomes so as to consume more than their income today. But in a closed economy there is nobody else you can borrow from. All consumers behave in the same way. Therefore, the real interest rate has to be such that consumers are satisfied with consuming less today than next year. Consumption must grow at the same pace as income, and this requires a real interest rate that is higher than the subjective rate of discount. Thus we see that an economy with high growth should have a high real interest rate and a high real return on investment. The capital stock per effective worker is determined by F ( k . ) 1 + / =p+g+8. This conclusion will be modified when we allow for international lending because international capital flows may equalize real interest rates and real returns on investment. Consumers in a growing economy may be able to borrow in the international credit market based on their high future incomes and financial cap- ital should flow to where the return on investment is highest. But international financial capital flows are limited by various barriers, so we would not expect real returns to be completely equalized. Therefore, we should still expect higher real returns in a growing economy. We will return to these issues once we have opened up our economy for international trade and borrowing and lending in international financial markets in Chapter 12