i dont see how the answer is 4k and not 6k...please help

ou invest $10,000 in a complete portfolio. The complete portfolio is composed of a risky asset with an expected rate of return of 15% and a standard deviation of 21% and a Treasury bill with a rate of return of 5%. How much money should be invested in the risk-free asset to form a portfolio with an expected return of 11%? Expected to oth of risk en of tobill I a) $6,000 proportion of risky! (proportion of tobil $4,000 We (15%* R) + (5%*(1-R)) R = 620 .60% $7,000 1190 = 15%R) + 5% - 570K 1 0% 10,000x68% 6,90 $3,000