How many distinct sequences of five letters can be made from the letters in EQUALS if each sequence must begin with L, end with Q, and no letter can appear in a sequence more than once?
Just insert "L" at the beginning and "Q" at the end of the following permutations:
{A, E, S} | {A, E, U} | {A, S, E} | {A, S, U} | {A, U, E} | {A, U, S} | {E, A, S} | {E, A, U} | {E, S, A} | {E, S, U} | {E, U, A} | {E, U, S} | {S, A, E} | {S, A, U} | {S, E, A} | {S, E, U} | {S, U, A} | {S, U, E} | {U, A, E} | {U, A, S} | {U, E, A} | {U, E, S} | {U, S, A} | {U, S, E} (total: 24)
