A portable radio requires an emf of 4.5 V. Olivia has only two non rechargeable 1.5-V batteries,

Question:

A portable radio requires an emf of 4.5 V. Olivia has only two non rechargeable 1.5-V batteries, but she finds a larger 6.0-V battery.
(a) How can she arrange the batteries to produce an emf of 4.5 V? Draw a circuit diagram.
(b) Is it advisable to use this combination with her radio? Explain.