Question

Stiind ca 7 stilouri si 6 pixuri costa 235 de lei, iar doua stilouri si 3 pixuri costa 80 de lei, determinati pretul unui pix si pretul unui stilou.

Answer 1

s=pretul unui stilou
p=pretul unui pix
2s+3p=80
3p=80-2s
7s+6s=235
7s+2(80-2s)=235
7s+160-4s=235
3s+160=235
3s=235-160
3s=75
s=25
2s+3p=80
2*25+3p=80
50+3p=80
3p=80-50
3p=30
p=10
          s=25  , p=10

Answer 2

7s+6p=235
2s+3p=80
9s+9p=235+80
9(s+p)=315
s+p=35
s=35-p
2(35-p)+3p=80
70-2p+3p=80
p=10 lei pixul
s=35-10=25 lei stiloul