Determine what this molecule should really be named.

2,2-ethylpent-3-ene

I get the answer 2,2-diethylpent-3-ene. Why would the answer be:
4-ethyl-4-methylhex-2-ene

2 answers

If you draw it out as a 2,2-diethylpent-3-ene but show one of the ethyl groups as -CH2CH3 instead of C2H5, it adds another C to make the longest chain a hexene. From there you add the substituents.
A chemist ran the reaction and obtained 5.80 g of ethyl butyrate. What was the percent yield?