Solution:The pattern followed here is :(1st number Γ 6) + 3 = 2nd number
(16, 99) β {(16 Γ 6) + 3} = 96 + 3 = 99
(13, 81) β {(13 Γ 6) + 3} = 78 + 3 = 81
Similarly,
(9, 57) β {(9 Γ 6) + 3} = 54 + 3 = 57
Hence, "(9, 57)" is the correct answer.