Obviously I too didn't get this right the first time.
But here is what I think:
13 letters with
3 - E's
2 - R's
2 - N's
2 - A's
The words to be formed are of the type E _, _, R
Consider all the single characters withour repititions i.e, we need to choose from : (M, D, I, T, R) + 1 from each of (E, N, A) = 8 characters.
So No of words = 8*7 = 56
Now we had excluded the possibility of (2 Es, 2Ns, 2A's)
So we have only 3 more words to consider:
Hence 56+3 = 59
"To dream anything that you want to dream, that is the beauty of the human mind. To do anything that you want to do, that is the strength of the human will. To trust yourself, to test your limits, that is the courage to succeed."
- Bernard Edmonds