Ans key: option 4 How Q If the product of 2 positive numbers is 9, then the possible - Maths -

Question

Ans key: option 4 How?
Q If the product of 2 positive numbers is 9, then the possible
value of the sum of their reciprocals lies in the
interval -

1   [ 1 3 , ∞ ) 2   [ 1 , ∞ ) 3   [ 4 9
, ∞ ) 4   [ 2 3 , ∞ )

Aarushi Mishra · Accepted Answer

Let the tow  numbers be  a and bab=9Apply A
M  and G M
 inequality on 1a and 1bA M ≥G M
1a+1b2≥1ab1a+1b2≥1ab1a+1b2≥191a+1b2≥131a+1b≥23Therefore,1a+1b lies in the interval [23, ∞)

Ans key: option 4. How? Q If the product of 2 positive numbers is 9, then the possible value of the sum of their reciprocals lies in the interval - 1 . [ 1 3 , ∞ ) 2 . [ 1 , ∞ ) 3 . [ 4 9 , ∞ ) 4 . [ 2 3 , ∞ )

Ans key: option 4. How?
Q If the product of 2 positive numbers is 9, then the possible value of the sum of their reciprocals lies in the
interval -

$1 . [\frac{1}{3}, \infty) 2 . [1, \infty) 3 . [\frac{4}{9}, \infty) 4 . [\frac{2}{3}, \infty)$