Answer
R, S, T, X, Y, Z
Work Step by Step
R, S, and T are placed in a queue in that order. R is the first item in the queue, followed by S, and then T.
One item is removed from the queue before a fourth item, X, is placed in the queue. The item that is removed is R.
One item is removed from the queue, the items Y and Z are placed in the queue, and then the queue is emptied by removing one item at a time. The item that is removed next is S, followed by T, X, Y, and finally Z.
