Yelena recites $P, Q, R, S, T, U$ repeatedly (e.g. $P, Q, R, S, T, U, P, Q, R, \ldots$ ). Zeno recites $1,2,3,4$ repeatedly (e.g. $1,2,3,4,1,2, \ldots$ ). If Yelena and Zeno begin at the same time and recite at the same rate, which combination will not be said?
(A) $T 1$
(B) $U 2$
(C) $Q 4$
(D) $R 2$
(E) $T 3$
To determine which combination will not be said, we list the letters and numbers recited by Yelena and Zeno in the table below.

| Yelena | $\mathrm{P}$ | $\mathrm{Q}$ | $\mathrm{R}$ | $\mathrm{S}$ | $\mathrm{T}$ | $\mathrm{U}$ | $\mathrm{P}$ | $\mathrm{Q}$ | $\mathrm{R}$ | $\mathrm{S}$ | $\mathrm{T}$ | $\mathrm{U}$ |
| :---: | :---: | :---: | :---: | :---: | :---: | :---: | :---: | :---: | :---: | :---: | :---: | :---: |
| Zeno | 1 | 2 | 3 | 4 | 1 | 2 | 3 | 4 | 1 | 2 | 3 | 4 |

Recognize that at this point Yelena has just said " $U$ " and thus will begin from the beginning, $P$, again. Similarly, Zeno has just said " 4 " and thus will begin from the beginning, 1, again. That is, the sequence of letter and number combinations listed above will continue to repeat. To determine which combination will not be said we need only compare the 5 answers with the 12 possibilities given in the table.

The only combination that does not appear in the table and thus that will not be said is $R 2$.

ANSWER: (D)

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