An owner of a small hotel with 5 rooms is thinking of buying T.V. sets to rent them to room occupants when demanded. He expects that about half of his customers will be willing to get sets on rent. He buys three T.V. sets. Assuming 100% occupancy at all times, find out the probability that: a customer who requests for T.V. will get one.

An owner of a small hotel with 5 rooms is thinking of buying T.V. sets to rent them to room occupants when demanded. He expects that about half of his customers will be willing to get sets on rent. He buys three T.V. sets. Assuming 100% occupancy at all times, find out the probability that: some demand will be refused.

A magnetic field set up using Helmholtz coils is uniform in a small region and has a magnitude of 0.75 T. In the same region, a uniform electrostatic field is maintained in a direction normal to the common axis of the coils. A narrow beam of (single species) charged particles all accelerated through 15 kV enters this region in a direction perpendicular to both the axis of the coils and the electrostatic field. If the beam remains undeflected when the electrostatic field is 9.0 xx 10^5 V m^-1 make a simple guess as to what the beam contains. Why is the answer not unique?