Question 10
A restaurant in Đà Nẵng offers four options: Bèo, Nậm, Bèo-and-Nậm Combo, and Xèo. An IMC participant visits on all six nights, 14–19 August, and orders exactly one option each night. He does not eat the same dish type on consecutive nights. Thus Bèo cannot be followed by Bèo or the Combo; a Combo on night 5 excludes Bèo, Nậm and Combo on nights 4 and 6. How many six-night order sequences are possible?
