23* a) mₐ = (4 + 8) : 2; mₐ = 6.
mₐ = (10 + 50) : 2; mₐ = 30.
mₐ = (25 + 45) : 2; mₐ = 35.
mₐ = (12 + 18) : 2; mₐ = 15.
24* mₐ = (a + b) : 2
a = 10
~
b = ?
~
(10 + b) : 2 = 12 /·2
10 + b = 24 /-10
b = 14
25* mₐ = (a + b + c) : 3
a = 30
b = 35
~
c = ?
~
(30 + 35 + c) : 3 = 25 /·3
65 + c = 75 /-65
c = 10
/robertinni
