Let number of cargo containers in the starting = 3x It drops 2/3 of cargo containers at the first port and takes 60 more. ⇒ Number of cargo containers when the ship left first port = 3x−(
2
3
×3x)+60=(x+60) Similarly, number ofcargo containers after leaving second port = on arriving at third port, ⇒
x+60
3
+11=48 ⇒
x+60
3
=48−11=37 ⇒ x+60=37×3=111 ⇒ x=111−60=51 ∴ Number of cargo containers in the ship at the starting = 3×51=153