g- grzybek , o - owca , b - banan
g + g + g = 30
3×g = 30 /÷3
g = 10
g + o + o = 20 ∧ g =10
10 + 2×o = 20
2×o =10 /÷2
o = 5
4×b + 4×b + o = 13 ∧ o =5
8×b + 5 = 13
8×b = 8 /÷8
b = 1
[(g +o)× (3×b) ]+ o = ? ∧ g = 10 ∧ o = 5 ∧ b = 1
[(g +o)× (3×b) ]+ o = ([10+5) × (3×1)] + 5 = [ 15 × 3 ] + 5 = 45 + 5 = 50
