AP EAMCET202021 Sep 2020Morning ShiftMathematicsPermutation and CombinationActual
If ( ^n P₄=1680 ), then (n= )
Options
- A6
- B12
- C10
- D8
Correct answer
D. 8
Step-by-step solution
( aligned & Since, ^n P₄=1680 & n(n-1)(n-2)(n-3)=1680 & n(n-1)(n-2)(n-3)=8 7 6 5 n=8 aligned ) Hence, option (d) is correct.