Two workers, one who can complete a job in 12 hours and another who can complete the same job in 8 hours, work together. How long will it take them to complete the job?

The rate of work is the reciprocal of the time taken to complete the job.
Worker 1's rate:

$$R_1 = \frac{1}{12} \text{ job/hour}$$

Worker 2's rate:

$$R_2 = \frac{1}{8} \text{ job/hour}$$

When working together, their rates add up.

$$R_{\text{combined}} = R_1 + R_2$$ $$R_{\text{combined}} = \frac{1}{12} + \frac{1}{8}$$

To add these fractions, find a common denominator, which is 24.

$$R_{\text{combined}} = \frac{1 \times 2}{12 \times 2} + \frac{1 \times 3}{8 \times 3}$$ $$R_{\text{combined}} = \frac{2}{24} + \frac{3}{24}$$ $$R_{\text{combined}} = \frac{2+3}{24}$$ $$R_{\text{combined}} = \frac{5}{24} \text{ job/hour}$$

The total time is the reciprocal of the combined rate.

$$T_{\text{total}} = \frac{1}{R_{\text{combined}}}$$ $$T_{\text{total}} = \frac{1}{\frac{5}{24}}$$ $$T_{\text{total}} = \frac{24}{5} \text{ hours}$$

To express this in hours and minutes:

$$T_{\text{total}} = 4 \frac{4}{5} \text{ hours}$$

Convert the fractional part to minutes:

$$\frac{4}{5} \text{ hours} \times 60 \text{ minutes/hour} = 4 \times 12 \text{ minutes} = 48 \text{ minutes}$$

So, the total time is 4 hours and 48 minutes.

The total time it will take them to finish the job altogether is $\boxed{\text{4 hours 48 minutes}}$.