14. (15 points) Build a highway. If A, B, and C work together, it can be completed in 90 days; if A, B, and D work together, it can be completed in 120 days; if C and D work together, it can be completed in 180 days. If A and B work together for 36 days, and the remaining work is completed by A, B, C, and D working together, how many more days are needed to complete the project?
【Solution】Solution: According to the analysis of the problem, we get:
The total efficiency of A, B, C, and D is: $\left(\frac{1}{90}+\frac{1}{120}+\frac{1}{180}\right) \div 2=\frac{1}{80}$, then the efficiency sum of A and B: $\frac{1}{80}-\frac{1}{180}=\frac{1}{144}$,
$$
\begin{aligned}
& \left(1-36 \times \frac{1}{144}\right) \div \frac{1}{80}, \\
= & \left(1-\frac{1}{4}\right) \div \frac{1}{80}, \\
= & \frac{3}{4} \times 80, \\
= & 60 \text { (days); }
\end{aligned}
$$

Answer: The remaining project, if worked on by A, B, C, and D together, will still require 60 days to complete.