rata rata 5 bilangan a b c x dan y adalah 11 jika rata rata abc 9 rata rata dari x dan y 'adalah.....

(a + b + c)/3 =9
(a + b + c) = 9 × 3
(a + b + c) = 27

(a + b + c + x + y)/5 = 11
(a + b + c + x + y) = 11 × 5
(a + b + c + x + y) = 55
(a + b + c) + (x + y) = 55
27 + (x + y) = 55
(x + y) = 55 - 27
(x + y) = 28

rata2 = (x + y) /2
rata2 = 28/2
rata2 = 14

semoga membantu ^_^