Question

Mihai si David au impreuna 55de cartonase Mihai si Radu au impreuna 77 de cartonase iar David si Radu 90 de cartonase.Cate cartonase are fiecare copil.

Answer 1

Răspuns:

Explicație pas cu pas:

Mihai + David              = 55

Mihai          +       Radu = 77

             David + Radu = 90

_______________________

Mihai + David + Radu = ( 55 + 77 + 90 ) : 2 = 222 : 2 = 111 cartonase

___________________________________________________

Cate cartonase are Mihai?

111 - 90 = 21 cartonase are Mihai

Cate cartonase are David?

55 - 21 = 34 cartonaseare David

Cate cartonase are Radu?

90 - 34 = 56 cartonase are Radu

Answer 2

m + d = 55

m + r = 77

d + r = 90

m + d + m + r = 55 + 77

2 × m + d + r = 132

2 × m + 90 = 132

2 × m = 132 - 90

2 × m = 42

m = 42 : 2

m = 21

d = 55 - 21

d = 34

r = 90 - 34

r = 56