What is the expected return and standard deviation of a portfolio consisting of $4500 invested in a risk-free asset with an 7.0-percent rate of return, and $1500 invested in a risky security with a 19.0-percent rate of return and a 24.0-percent standard deviation? 6.000 percent, 10.00 percent 18.000 percent, 16.00 percent 16.00 percent, 18.000 percent 10.00 percent, 6.000 percent