99 Percentile Qs Bank for JEE MainMathematicsSequences and Series
If x+y=60, x>0, y>0 , then the maximum value of x y^3 is
Options
- A(15)^4 25 3
- B45(15)^3
- C(45)^3 9 5
- D(45)^4 3
Correct answer
D. (45)^4 3
Step-by-step solution
Given, x+y=60 By AM GM array ll & x+ y 3 + y 3 + y 3 4 ( x y^3 27 )^ 1 / 4 & x+y 4 ( x y^3 27 )^ 1 4 & 60 4 ( x y^3 27 )^ 1 4 & x y^3 27 (15)^4 & x y^3 3^3 3^4 5^4 x y^3 (45)^4 3 array Maximum value of x y^3 is (45)^4 3 .