If a being were located 240 million light-years away from Earth and had the ability to observe it, they would not see dinosaurs walking the Earth. Here's why:
When we talk about observing objects at such vast distances, it's important to consider the concept of the speed of light. Light travels at a finite speed, approximately 299,792 kilometers per second (about 186,282 miles per second) in a vacuum. This means that when we observe objects in space, we are actually seeing them as they were in the past, based on the time it takes for their light to reach us.
In the case of the hypothetical being 240 million light-years away, the light from Earth that they observe would have taken 240 million years to reach them. This means that they would see Earth as it was 240 million years ago, not as it is today.
Dinosaurs became extinct around 65 million years ago, so if this being were observing Earth from 240 million light-years away, they would see a version of Earth that predates the existence of dinosaurs. They would not witness dinosaurs walking the Earth in real-time.
It's worth noting that observing objects at such immense distances poses significant challenges due to cosmic expansion, the finite age of the universe, and the limited range of electromagnetic radiation. Nonetheless, based on our understanding of the speed of light and the timeline of Earth's history, the scenario you described would not allow for the observation of dinosaurs on Earth.