Answer:
You should invest 26.8% of your complete portfolio in treasury bills to earn an expected rate of return of 11% on a complete portfolio.
Explanation:
To begin with, first we have to calculate the return of P portfolio consisting of X and Y securities.
Expected Return (ER) = (Weight of X*Return of X) + ( Weight of Y*Return of Y)
ER = (0.6*0.14) + (0.4*0.12)
ER = 0.084 + 0.048
ER = 0.132 or 13.2%
Now, we have to compute the weight of treasury bills in complete portfolio:
ER = (Weight of TB*Return of TB) + (Weight of P*Return of P)
ER = (wTB * rTB) + (wP * rP)
ER= (wTB * rTB) + rP * (1-wTB)
0.11 = (wTB * 0.05) + 0.132*(1-wTB)
0.11= 0.05wTB + 0.132 - 0.132wTB
0.11 = -0.082wTB + 0.132
Let's make the Weight of Treasury Bills subject:
0.082wTB = 0.132 - 0.11
0.082wTB = 0.022
wTB = 0.022/0.082
Weight of Treasury Bills = 0.268 or 26.8%