Family

reminder = 3840-2560 =1280
spent himself = 1/8 × 1280 = 160
C. 5/6b = 140
(*assuming b = total number of cards)
If the piles have an equal number of cards and 5 out of the 6 piles were put in the collection, 5/6 of the cards were put into the collection. The total number of cards put in the collection is 140, so 5/6b=140.
The answer to ur problem is 1.27945
The awnser is 2,944,000,000