Calculate the correct dosage in tablets or capsules for the given medication orders.

1)
The doctor orders $160 \text{ mg}$ of medication.
The medication is available in $80 \text{ mg}$ tablets.

Number of tablets to be given:

$$\frac{160 \text{ mg}}{80 \text{ mg/tablet}} = 2 \text{ tablets}$$

The patient should be given $\boxed{\text{2 tablets}}$.

2)
The order is for a dose of $300,000 \text{ units}$ of penicillin.
The capsules are available in $100,000 \text{ units}$.

Number of capsules to be given per dose:

$$\frac{300,000 \text{ units}}{100,000 \text{ units/capsule}} = 3 \text{ capsules}$$

The patient should be given $\boxed{\text{3 capsules}}$.

3)
The patient is to receive Drug B, $10 \text{ mg}$.
Each tablet is $2.5 \text{ mg}$.

Amount of Drug B to give the patient (in tablets):

$$\frac{10 \text{ mg}}{2.5 \text{ mg/tablet}} = 4 \text{ tablets}$$

You would give the patient $\boxed{\text{4 tablets}}$ of Drug B.