Question
Question: If a, b, c, d are four positive real nos. such that abcd =1 then least value of (a + 4) (b + 4) (c +...
If a, b, c, d are four positive real nos. such that abcd =1 then least value of (a + 4) (b + 4) (c + 4) (d + 4) is
A
16
B
125
C
25
D
625
Answer
625
Explanation
Solution
Q abcd = 1
Using A.M. ³ G.M., we get a + b + c + d ³ 4
for minimum
a = b = c = d = 1
\ Minimum value of
(a + 4) (b + 4) (c + 4) (d + 4) = 625