NSTU has to selete exactly three volunteer's for a seminar the volunteers are to seleted from seven students of whom four Ana, Kajol, Lopa and Mira are form 6th batch and ret three volunteers Shamol, Parvez and Tipu are from 7th Batch the organiztion must observe the following restriction At least one student from each batch must selete as volunteer. If Ana is seleted, Tipu can ot be selected.
If either Lopa or Mira is seleted, the other must also be sleeted If either kajol or Parvez is sleeted, the other also be sleeted