Can you help me write a short sentence (native speakers of English are welcome)?

[Brightgreen]

The idea of the sentence is - the carton box (for a parcel) should be firm enough so that if we put there something that is four times heavier than the initial object the box is not destroyed. What I've come up with is - It (the box) should be firm enough to carry four times the weight of the parcel... Is that correct? Thanks in advance for any better ideas.

 

[Raymott]

The idea of the sentence is - the carton box (for a parcel) should be firm enough so that if we put there something that is four times heavier than the initial object the box is not destroyed. What I've come up with is - It (the box) should be firm enough to carry four times the weight of the parcel... Is that correct? Thanks in advance for any better ideas.

Yes, that might work, but note that "four times heavier" strictly means "five times as heavy". Your specifications indicate that you mean that the box should be able to carry a weight four times as heavy as the parcel it's used for - hence your final sentence is correct.

 

[Brightgreen]

Ok, thanks!