Double Decker bus can have 80 passengers 35 in upper and 40 in lower deck. how many ways can a group of 80 passengers...

Question

A double Decker bus can accommodate 80 passengers 35 in upper deck and 40 in lower deck. In how many ways can a group of 80 passengers be accommodated if 5 refuse to sit in the lower deck and 10 refuse to sit in the upper deck