Please refer to the link below

https://engineering.careers360.com/articles/wbjee-eligibility-criteria

Excerpt from link -

Marks Required: General category candidates should have secured an aggregate of 45% and reserved category candidates should have scored 40% in the above three subjects taken together to be eligible for WBJEE 2018. All candidates are required to have qualified English in 10+2 with atleast 30% marks. The board of the qualifying examination must be recognized by Central and State government concerned.