Answer:
brown = 12
yellow = 30
orange = 36
Step-by-step explanation:
let 'b' = # brown
let '18+b' = # yellow
let '3b' = #orange
add them together and set equal to 78
b + 18 + b + 3b = 78
5b + 18 = 78
5b = 60
b = 12
y = 12 + 18 = 30
o = 3(12) = 36
12 + 30 + 36 = 78
