In a music school, every one of the 94 students plays at least one of guitar, keyboard and tabla. The number after each instrument is its total number of players; the box gives how many play BOTH of each pair (including those who play all three). How many play all three?

Question

Accepted Answer

8. n(G K T) = n(G) + n(K) + n(T) - n(G K) - n(G T) - n(K T) + n(G K T). So 94 = 123 - 37 + ?, giving ? = 8. (29 is 123 - 94, forgetting the pairs.)

In a music school, every one of the 94 students plays at least one of guitar, keyboard and tabla. The number after each instrument is its total number of players; the box gives how many play BOTH of each pair (including those who play all three). How many play all three?

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