In how many districts ways can the letters in ENGINEERING be arranged?
There are 3 Es, 3 Ns, 2 Gs, 2 Is
in the 11 letters.
so how many different things do we have?
E, N , G, I or 4 different letters
If all 11 were different there would be 11! ways
However take away 3!, 3! , 2! , 2!