Carcass wrote:
How many different four-letter words can be formed (the words need not be meaningful) using the letters of the word GREGARIOUS such that each word starts with G and ends with R?
(A) \(8P_2\)
(B) \(\frac{8P_2}{2!*2!}\)
(C) \(8P_4\)
(D) \(\frac{8P_4}{2!*2!}\)
(E) \(\frac{10P_2}{2!*2!}\)
Place one G in the first slot and one R in the last slot:
G __ __ R
The remaining letters, {G, R, E, A, I, O, U, S}, can be arranged in the remaining 2 slots in \(8P_2\) [no
indistinguishable(same) objects nor repetition]. The answer is
(A).
Note: Since the two G’s in the base word are indistinguishable, the word G 1 G 2 AR is the same as G 2 G 1 AR. Hence, the internal arrangement of the G’s or, for the same reason, the R’s is not important.