Răspuns:
Explicație pas cu pas:
Carti tiparite Carti ramase de tiparit
Saptamana 1 X/5 4X/5
Saptamana 2 (4X/5)·1/3 (4X/5)·2/3
Saptamana 3 [(4X/5)·2/3]·1/4 [(4X/5)·2/3]·3/4
Saptamana 4 [(4X/5)·2/3]·3/4=1320 0
[(4X/5)·2/3]·3/4=1320 ⇒(4X·2·3)/(5·3·4)=1320
Dupa simplificare se obtine X·2/5=1320 ⇒2X=1320·5 ⇒X=1320·5/2 ⇒X=660·5 ⇒X=3300 carti