Answer:
[tex]3w+45=557[/tex]
Step-by-step explanation:
Let the weight of box Y be w kg.
Box X weighs 33 kg more than Box Y, then the weight of box X is
[tex]w+33[/tex] kg.
Box Z weighs 12 kg more than Box Y, then the weight of box Z is
[tex]w+12[/tex] kg.
The total weight of all boxes is
[tex]w+(w+33)+(w+12)=w+w+33+w+12=3w+45[/tex] kg
Jane measured the total weight of all the boxes and it was found to be 557 kg, therefore,
[tex]3w+45=557[/tex]
or
[tex]3w=512[/tex]