Why did the merchants in california make a lot of money during the gold rush

Well, durign the gold rush people had "rushed" all the way to California from all over the world. (Even china!) Ultimately they found nothing- thus made nothing. However, the people who did make something out of nothing were merchants. Mainly because while people moved across land at a time where resources were scarce what did they need? The essentials to start. Essentials like food, clothing, tools, a place to stay.

Hopefully this helps! 

They made a lot of money because they needed supplies and food during the gold rush and the merchants knew that they were their only sorce so they had high prices that resulted in a lot of money