James saved 24.60 dollars, and we know Dillon saved 2/3 of the amount James saved.
Dillon's amount: 2/3 * 24.60 = 16.40
So we have two amounts:
James = 24.60 dollars
Dillon = 16.40
Mara = 16.40 * 2 = 32.80 dollars.
The question is asking for the total, so we add them together:
24.60 + 16.40 + 32.80 = 73.8 dollars.