EBE, BEE, and NTW are different 3-letter strings constructed from the word BETWEEN. Find the total number of strings.
There are 73 distinct permutations taken 3 letters out of 7: B, E, T, W, E, E, N:
{B, E, E} | {B, E, N} | {B, E, T} | {B, E, W} | {B, N, E} | {B, N, T} | {B, N, W} | {B, T, E} | {B, T, N} | {B, T, W} | {B, W, E} | {B, W, N} | {B, W, T} | {E, B, E} | {E, B, N} | {E, B, T} | {E, B, W} | {E, E, B} | {E, E, E} | {E, E, N} | {E, E, T} | {E, E, W} | {E, N, B} | {E, N, E} | {E, N, T} | {E, N, W} | {E, T, B} | {E, T, E} | {E, T, N} | {E, T, W} | {E, W, B} | {E, W, E} | {E, W, N} | {E, W, T} | {N, B, E} | {N, B, T} | {N, B, W} | {N, E, B} | {N, E, E} | {N, E, T} | ... (total: 73)
