How many distinct sequences of four 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?
The four letters of this "word" are comprised of the starting letter L and the final letter Q
With the information above already established, we know that the "word" looks like L __ __ Q in construction. We also know that the letters E, U, A, and S still remain in the pool. No letter can appear more than once in a given sequence either.
There are four choices for the second letter of this "word." There, then, remains three possibilities for the third slot because the letter in the second slot may not be repeated. The product of 4 and 3 would also be the number of distinct sequences that exist.