Q21

[Nina]

how should we solve this question?

Thanks in advance!

[patrice.antoine]

We can best approach this question by first asking which performances are most limited in their placements. By first limiting performances, we can then limit the instruments shared.

We were told that either N or T is performed second. We also note that they share one instrument in common - the fiddle. Because each performance must share an instrument placed either before or after it, and the only two performances that play the fiddle are N and T we know that furthest N or T can be placed is in slot 3. The fiddle cannot be shared after slot 3. Therefore, the fiddle cannot be shared by the third and fourth pieces.