I believe their website is very clear on it's policy.

http://www.cathaypacific.com/cpa/en_...ckedbaggage#WS

- No restriction on the number of pieces

- Maximum combined weight:
First: 40kg (88lbs)
Business: 30kg (66lbs)
Premium Economy: 25kg (55lbs)
Economy: 20kg (44lbs)