Question

Ajutatima la ex 4 va rog frumos

Answer 1

x=nr de probleme
2x/5=saptamana 1
x-2x/5=3x/5=rest
3x/5×5/12=x/4=saptamana 2
2x/5+x/4+49=x
8x+5x+980=20x
7x=980
x=140 probleme in total
x/4=140/4=35 probleme saptamana 2

Answer 2

Metoda mersului invers 
ultimul rest este 12/12-5/12=7/12 (49probleme)
1/12reprezinta 49:7= 7(probleme )
A 2-a sapt..a rezolvat 5/12,deci 5x7=35(probl)
3/5 ,primul rest reprezinta 7x12==84(probl)
5/5 nr total de probl. reprezinta 84:3X5=140 probl.