Răspuns:
Explicație pas cu pas:
x - 20%·x = 9600 lei =>
x - 20x/100 = 9600 lei =>
⁵⁾x - x/5 = ⁵⁾9600 lei =>
5x - x = 48000 lei =>
4x = 48000 lei =>
x = 48000 : 4 => x = 12000 lei
a/2 = b/5 = c/8 ; 2a +b +3c = 5
a/2 = b/5 => a = 2b/5
b/5 = c/8 => c = 8b/5 =>
4b/5 + 5b/5 + 24b/5 = ⁵⁾5 =>
33b = 25 =>
b = 25/33
a = 10/33
c = 40/33
2a = 20/33 ; b = 25/33 ; 3c = 120/33 =>
2a+b+3c = (20+25+120)/33 = 165/33 = 5
