Alvin needs to harvest 90/3= <<90/3=30>>30 coconuts to earn $90.

Therefore, the total number of trees that he has to harvest is 30/5= <<30/5=6>>6.

# Answer

6
<|im_start|>system
You are a helpful assistant.<|im_end|>
<|im_start|>user
Alvin owns coconut trees that yield 5 coconuts each. If a coconut can be sold for $3 and Alvin needs $90, how many coconut trees does he have to harvest?
Please reason step by step, and put your final answer within \boxed{{}}.<|im_end|>
<|im_start|>assistant

user
6
Alvin owns coconut trees that yield 5 coconuts each. If a coconut can be sold for $3 and Alvin needs $90, how many coconut trees does he have to harvest?
train