1) What is the value of x if x/2=n!
a)??
b)360
c)??
d)520
e)1440  Reply With Quote

E is the Ans ..

2*7!= 1440

Saurabh Malpani  Reply With Quote

Can u explain how u got it

Thanks  Reply With Quote

E is the ans since 2*6! = 1440. But I just simply do the computation.  Reply With Quote

how to do such a calculation in ONE MINUTE???
actually this is my only problem...i do not find the question difficul, but the timeeeeeeeeeeeeeeeeeeeeeeeeeee  Reply With Quote

Yes, i also having the same problem as lorcar!  Reply With Quote

1! = 1
2! = 2
3! = 6
4! = 24
5! = 120
6! = 720
7! = 5040
From answer choices, we can guest x=1440.   Reply With Quote

one of my friend told that, since this is not a large number, we can remember it. And I have to admit that he has very good memory.  Reply With Quote

9. Anyone can explain this question?  Reply With Quote

10. Originally Posted by bscout Anyone can explain this question?
Very simple, if we use reverse substitution.

Factorial of a number is 1*2*3*4*...*n.
Hence possible factorials are :
1! = 1
2! = 2
3! = 6
4! = 24
5! = 120
6! = 720
7! = 5040

Now x = 2*n! If we look for all the options, only 1440 makes sense.  Reply With Quote