Can whales eat sharks

Depends on the species of whale.

The whales that are filter feeders - baleen whales - CAN'T eat sharks. They don't have the teeth to bite them into chunks, and they're too big to swallow whole.

Now, to be picky, a baleen whale would be able to eat a really small shark, like a newborn, or some of the smallest species. But it'd be accidental, and not part of the regular diet.

A big, toothed whale like the sperm whale, could probably eat a shark by intent. But aren't known to do so.