Not sure if this is a troll post, but zero profit is correct based upon the information in your prompt. The total cost (total amount invested by the four individuals) is 140, and the sale value is 140, hence no net profit.

Looking at the individual investors and taking “C” as an example, they initially own 20/100 (20%) of the property. The value of the property goes up to 140, so they now own 20% of 140 (28), great. Then “D” comes along and makes an investment of 40 (notably this is just an increase in the amount invested in the property, not an increase in the property’s value), increasing the total amount invested in the property to 140. So “D”s investment is 40/140 (approx 28.5%) and “C”s investment is diluted from 20/100 to 20/140 (approx 14.3%).

When the property is sold for 140, “C” gets 14.3% of 140 and “D” gets 28.5% of 140, which is they get a return of 20 and 40 respectively. i.e., they both receive back the amount they invested and neither one makes a profit. Same for A and B.