Answer:
The number of seashells he have in his collection all together is 140.
Explanation:
Given:
Stanley has a collection of seashells. He found 35% of his collection on Florida beaches.
Stanley has 49 seashells from Florida.
Now, to find the number of seashells of his collection altogether.
Let the number of seashells all together be

Percentage of seashells found on Florida beaches = 35%.
Number of seashells found on Florida beaches = 49.
Now, to get the number of seashells altogether we put an equation:

⇒

⇒

⇒

Dividing both sides by 0.35 we get:
⇒

Therefore, the number of seashells he have in his collection all together is 140.