3. (8 points) A bag of rice, Liu Bei can finish it alone in 5 days, Guan Yu can finish it alone in 3 days; a bag of wheat, Guan Yu can finish it alone in 5 days, Zhang Fei can finish it alone in 4 days. Liu Bei's daily food intake is less than Zhang Fei's daily food intake by $\qquad$ $\%$.
【Answer】Solution: Let Guan Yu's daily food intake be the unit "1", then Liu Bei's daily food intake is: $3 \div 5=\frac{3}{5}$, and Zhang Fei's daily food intake is: $5 \div 4=\frac{5}{4}$
$$
\begin{aligned}
& \left(\frac{5}{4}-\frac{3}{5}\right) \div \frac{5}{4} \\
= & \frac{13}{20} \div \frac{5}{4} \\
= & 52 \%
\end{aligned}
$$

Answer: Liu Bei's daily food intake is $52\%$ less than Zhang Fei's daily food intake.
Therefore, the answer is: 52.