NIMCET 2018 — Mathematics PYQ
NIMCET | Mathematics | 2018If a1,a2,a3,…,an are positive real numbers whose product is a fixed number C, then the minimum value of a1+a2+…+an is
Choose the correct answer:
- A.
nn(2c)1
- B.
n(n+1)C1
n(C)1/n
Explanation
Concept
Arithmetic Mean (AM): A=n∑xi, \quad xi= data set value, n= number of values
Geometric Mean (GM): G=(x1×x2×⋯×xn)n1
We know that AM≥GM
⇒na1+a2+…+an≥(a1a2…an)n1
⇒a1+a2+…+an≥n(C)n1
Hence, minimum value of (a1+a2+…+an)=n(C)n1
Calculation
Here, a1×a2×⋯×an=C
AM≥GM
⇒(na1+a2+⋯+an)≥((a1×a2×⋯×an)n1)
⇒(a1+a2+⋯+an)≥(Cn1)×n
So, the minimum value of (a1+a2+⋯+an) \text{ is } n(C)n1.
Hence, option (3) is correct.
Explanation
Concept
Arithmetic Mean (AM): A=n∑xi, \quad xi= data set value, n= number of values
Geometric Mean (GM): G=(x1×x2×⋯×xn)n1
We know that AM≥GM
⇒na1+a2+…+an≥(a1a2…an)n1
⇒a1+a2+…+an≥n(C)n1
Hence, minimum value of (a1+a2+…+an)=n(C)n1
Calculation
Here, a1×a2×⋯×an=C
AM≥GM
⇒(na1+a2+⋯+an)≥((a1×a2×⋯×an)n1)
⇒(a1+a2+⋯+an)≥(Cn1)×n
So, the minimum value of (a1+a2+⋯+an) \text{ is } n(C)n1.
Hence, option (3) is correct.

