Problem Solving

What is the minimum value of x + 100/x ? if x>0.

A.20
B.101
C.52
D.100
E.0
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just by hit & trial put x = 100/x;

It gives x= +10 & -10. Take x = 10 only as x>0.

So value of (x + 100/x) @ x = 10 is 20.

Now to confirm if 20 is minimum value.

try @ x = 1 (Lesser than x = 10 value) => (x + 100/x) is 101 (More than 20).

try @ x = 20 (Greater than x = 10 value) => (x + 100/x) is 25 (More than 20).

So Min. value of (x + 100/x)is 20