Question

Va rog dau 25 de puncte. Costel cumpara cu 4 supra 6 o minge. Bunica îi mai da 6 lei. Cu 2 supra 3 din noua suma o carte. Îi raman 8 lei. Cati lei a avut la inceput?

Answer 1

a- (4/6)*a + 6 - (2/3)*[a-(4/6)*a+6] =8 
a-4a/6 +6 - (2/3)*(a-4a/6+6) = 8
a-4a/6+6 - (2/3)*[(6a-4a+36)/6] = 8
(6a-4a+36)/6 - (4a+72)/18 = 8
(2a+36)/6 - (4a+72)/18 = 8
(6a+108-4a-72)/18 = 8
2a+36= 144 => 2a= 108 => a=54

Answer 2

a- (4/6)*a + 6 - (2/3)*[a-(4/6)*a+6] =8 
a-4a/6 +6 - (2/3)*(a-4a/6+6) = 8
a-4a/6+6 - (2/3)*[(6a-4a+36)/6] = 8
(6a-4a+36)/6 - (4a+72)/18 = 8
(2a+36)/6 - (4a+72)/18 = 8
(6a+108-4a-72)/18 = 8
2a+36= 144 => 2a= 108 => a=54