Current Attempt in Progress

If Baxter's Barber Shop is able to cut the $1$st customer's hair in $30$ minutes, the $2^{nd}$ customer's hair in $28\mathrm{.}5$ minutes, the $4^{th}$ customer's

hair in $27\mathrm{.}08$ minutes, and the $8^{th}$ customer's hair in $25\mathrm{.}72$ minutes, what is Baxter's learning curve?

Learning Curve $=$

$\%$

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