Question

intr-o zi, 15 fete si 10 din grupul micii ecologisti au plantat 420 panselute. A doua zi 12 fete si 10 baieti eu plantat 360 panselute. Cate panselute a plantat un baiat si cate o fata pe zi?

Answer 1

15 f + 10 b = 420 panselute
12 f + 10 b = 360 panselute

Rezolvare:
420 - 360 = 60 panselute
60 : 3 = 20 panselute ( 1 fata)

420 - 20 x 15 = 420 - 300 = 120 
120 : 10 = 12 panselute ( 1 baiat)

Verificare:
15 x 20 + 10 × 12 = 300 + 120 = 420 panselute
12 × 20 + 10 x 12 = 240 + 120 = 360 panselute