The black line segment was originally created by my sister, and the blue line segment was originally created by my sister.

The green line segment is for two people.

The red line segment was left by each of them.

As can be seen from the figure, the original 1/2 (that is, the original sister) of the sister can be calculated as follows:

180-30-24 = 126 (yuan)

They originally had * * *: 126× 3 = 378 (yuan).

* * * Remaining: 378- 180-30 = 168 (Yuan)

Checking calculation: sister surplus: 126-30 = 96, sister surplus:126× 2-180 = 72,96-72 = 24. Meet the meaning of the question