Answer:
2/3
Step-by-step explanation:
Since the length increases by 0.5 cm every second, after 8 seconds the length will increase by 4 cm. 12 + 8 + 12 + 8 = 40, and 40 - (16 + 16) = 8. 8/2 = 4, so the width is now 4. 16 * 4 = 64, and 12 * 8 = 96. 64/96 = 2/3.