Explanation:
To determine how many days Ade and Bayo will take to complete the job together, follow these steps:

1. Calculate Individual Work Rates:
- Ade's work rate is \(\frac{1}{12}\) of the job per day.
- Bayo's work rate is \(\frac{1}{18}\) of the job per day.

2. Combine Their Work Rates:
- Together, their combined work rate is:
\[
\frac{1}{12} + \frac{1}{18}
\]

3. Find a Common Denominator:
- The least common multiple of 12 and 18 is 36. Thus:
\[
\frac{1}{12} = \frac{3}{36}
\]
\[
\frac{1}{18} = \frac{2}{36}
\]
\[
\frac{1}{12} + \frac{1}{18} = \frac{3}{36} + \frac{2}{36} = \frac{5}{36}
\]

4. Calculate the Time Taken Together:
- If their combined work rate is \(\frac{5}{36}\) of the job per day, then the total time required to complete the job is the reciprocal of this rate:
\[
\text{Time} = \frac{36}{5} = 7.2 \text{ days}
\]


Ade and Bayo, working together, will complete the job in 7.2 days.

The correct answer is B. 7.2 days.