A man earns 24,000 per month. He spends one-third of his income on personal expenditure. Half of the remaining income is invested in a scheme for 15% interest per annum. After investing half of the remaining income is invested in a scheme which gives 10% income per annum. The remaining lies in a bank where it earns an interest of 4% per annum. The effective rate of interest earned by the man on his investments by the end of the year is
