Question

if 3nc2 = 2nc1 find n​

Answer 1

Answer:

Find n, if

2n

C

3

:

n

C

2

=52:3

n

C

2

2n

C

3

=

3

52

∴

2

n(n−1)

3×2×1

2n(2n−1)(2n−2)

=

3

52

∴

3×2×1×n(n−1)

2n(2n−1)2(n−1)

×2=

3

52

∴

3

4(2n−1)

=

3

52

∴4(2n−1)=52

∴2n−1=

4

52

∴2n−1=13

∴2n=13+1

∴2n=14

∴n=7