If the P/E ratio on the S&P 500 is 10

If the P/E ratio on the S&P 500 is 10

Question
	

If the P/E ratio on the S&P 500 is 10, given historical earnings growth patterns, what would be a reasonable estimate of long-run future expected rates of return on the stock market? Assume a long-run inflation rate of 2.5% per annum.