[問題]天山7-13請教各位大大

[lovy]

If n is the greatest positive integer for which 2^n is a factor of 10!,then n=?

A 2
B 4
C 6
D 8
E 10

ANS D

[FrankChang]

2^n是10!的因數,n要最大,
就看10!可以最多提出幾個2就知道了,
odd不看,2=2^1,4=2^2,6=2*3,8=2^3,10=2*5,
1+2+1+3+1=8.

[lovy]

tks a lot