Four big sandwiches are divided among m students (m>4). First three are divided among m and the last one divided among (m-4). 4 of the students are full and want none of sandwiches and one of them likes the taste of the sandwich very much and eats a piece of all four sandwiches. What portion of the four sandwiches did he eat?

3/m + 1/(m-4) = 4(m-3)/m(m-4)

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There are 4 sandwiches.

3 sandwiches are divided by m pieces, and one piece is 3/m.

1 sandwich is divided by (m-4) pieces, and one piece is 1/(m-4).

One student eats a piece of all FOUR sandwiches.

Therefore,

he eats total of 4 pieces !
If so, the OA should be

3 * (3/m) +

1 * ( 1/(m-4) ) !

At what point am I mistaken here?

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