Answer
Therefore, we conclude that is needed 72000 salmon eggs  to produce 18 adult salmon.
'Step-by-step explanation'
We know that scientists study ways to increase the population of wild salmon. We know that for every 8,000 eggs, only 2 adults may survive.
We calculate how many salmon eggs may be needed to produce 18 adult salmon. Â
Therefore, we conclude that is needed 72000 salmon eggs  to produce 18 adult salmon.