a,b,c and d are 4 positive real numbers.and their product is 1.what is minimum value of (1+a)(1+b)(1+c)(1+d)
a)4
b)1
c)16
d)18
a)4
b)1
c)16
d)18
a, b, c & d are 4 real nos which are positive and not distinct. All can take the same minimum value and their product is 1.
a*b*c*d = 1 and a=b=c=d.
(1+a)(1+b)(1+c)(1+d) = (1+a)^4.
So ans choice must be a perfect number which satisfies the 4th power.
IMO C.
Hope its right.
