Solution:The pattern followed here is :(1st number + 2nd number) Γ 5 = 3rd number
(5, 11, 80) β (5 + 11) Γ 5 β (16 Γ 5) = 80
(6, 12, 90) β (6 + 12) Γ 5 β (18 Γ 5) = 90
Similarly,
(7, 17, 120) β (7 + 17) Γ 5 β (24 Γ 5) = 120
Hence, (7, 17, 120) is the correct answer.