I couldn't see an appropriate category for this so apologies for the AIBU, but I could do with some urgent advice 
I'm currently broiling a 2.7kg salt beef joint, but the recipe I'm using is based on a joint weighing 1.6kg and says broil for 2.5hours.
I divided 2.5 by 1.6 then multiplied by 2.7 and got 4 hours 20 minutes! Is this correct?
I can't seem to find any general time per weight guides for broiling beef.