Let a, B, C ∈ positive real number, a + B + C = 7, then the maximum value of √ a + √ B + √ C is

Let a, B, C ∈ positive real number, a + B + C = 7, then the maximum value of √ a + √ B + √ C is

(√a+√b+√c)^2=a+b+c+2√ab+2√bc+2√ac=7+2√ab+2√bc+2√ac