Answer: $105000
Step-by-step explanation:
From the question, we are informed that Serena owned real estate worth $210,000 with her spouse in joint tenancy with the right of survivorship when she died and that she contributed $50,000 to the original cost of the property and her spouse contributed the remaining $100,000.
The amount, that will be included in Serena's gross estate will be:
= $210,000 × 50%
= $210000 × 0.5
= $105,000
It should be noted that only 50% will be included since she owes the property with her spouse in joint tenancy.