JAMB - Mathematics (2018 - No. 33)
In how many ways can the letters LEADER be arranged?
72
144
360
720
Giải thích
The word LEADER has 1L 2E 1A 1D and 1R making total of 6! \(\frac{6}{1!2!1!1!1!}\) = \(\frac{6!}{2!}\)
= \(\frac{6 \times 5 \times 4 \times 3 \times 2 \times 1}{2 \times 1}\)
= 360