Answer: 1.50
Step-by-step explanation:
Isabel's portfolio beta is a weighted average of the individual stock betas.
= Weight of stock A * Stock A beta + Weight of stock B * Stock B beta + Weight of stock n * Stock n beta
= (20% * 0.4) + (30% * 1.2) + ( 25% * 2.5) + (25% * 1.75)
= 0.08 + 0.36 + 0.625 + 0.4375
= 1.5025
= 1.50