Răspuns:
Explicație pas cu pas:
n = numarul pieselor
30% = 30/100 = 3/10
40% = 40/100 = 2/5
75% = 75/100 = 3/4
Prima saptamana 3n/10
A doua saptamana 2/5*3n/10 = 6n/50 = 3n/25
A treia saptamana 3/4*3n/25 = 9n/100
A patra saptamana n - 3n/10 - 3n/25 - 9n/100
= 100n/100 - 30n/100 - 12n/100 - 9n/100 = 49n/100
a)
49n/100 = 980
n = 980*100/49 = 2000 piese
b) Prima saptamana 3*2000/10 = 600 piese
A treia saptamana 9*2000/100 = 180 piese
(180/600)*100 = 30%