Question

va rog ajutati-ma este urgent
ex 8

Answer 1

Notez bani in total = y
I zi : 1/ 3 × y = y/3
II zi : 1/4 × rest = 1/4 × [y - (1/3 × y)] = 1/4 × 2y/3  =  y/6
III zi : 1/2 × noul rest = 1/2 × [y - ( y/3 + y/6)] = 1/2 × y/2 = y/4
Raman 30 de lei 

y = y/3 + y/6 + y/4 + 30 
y - y/3 - y/6 - y/4 =30  (aducem la acelasi numitor)
24y/24 - 8y/24 - 4y/24 - 6y/24 = 30 
6y/24 = 30 ⇒ 6y = 24 × 30 
                      6y = 720
                      y = 120 (banii cu care a plecat in excursie)

I zi : y/3 = 120 ÷ 3 = 40 lei 
II zi : y/6 = 120 ÷ 6 = 20 lei
III zi : y/4 = 120 ÷ 4 = 30 lei