Find how many original oranges remain, then find the total after adding, then express as a fraction.<br><br>
&bull; Rotten oranges = \( \frac{5}{8} \times 72 = 45 \)<br>
&bull; Original oranges not rotten = 72 − 45 = 27<br>
&bull; After removing rotten and adding 18 fresh: total = 27 + 18 = 45<br>
&bull; Fraction from original batch = \( \frac{27}{45} \)<br>
&bull; Simplify: divide numerator and denominator by 9.<br>
&bull; \( \frac{27}{45} = \frac{27 \div 9}{45 \div 9} = \frac{3}{5} \)<br><br>
Final Answer: \( \frac{3}{5} \)