Sam dumps tea for $6$ hours at a constant rate of $60$ tea crates per hour. Eddie takes $4$ hours to dump the same
amount of tea at a different constant rate. How many tea crates does Eddie dump per hour?

[i]Proposed by Samuel Tsui[/i]

[hide=Solution]
[i]Solution.[/i] $\boxed{90}$
Sam dumps a total of $6 \cdot 60 = 360$ tea crates and since it takes Eddie $4$ hours to dump that many he dumps at a rate of $\dfrac{360}{4}= \boxed{90}$ tea crates per hour.
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1. First, calculate the total number of tea crates Sam dumps. Sam dumps tea for 6 hours at a constant rate of 60 tea crates per hour. Therefore, the total number of tea crates Sam dumps is:
   \[
   6 \text{ hours} \times 60 \text{ tea crates/hour} = 360 \text{ tea crates}
   \]

2. Next, we know that Eddie takes 4 hours to dump the same amount of tea crates. To find Eddie's dumping rate, we divide the total number of tea crates by the number of hours Eddie works:
   \[
   \frac{360 \text{ tea crates}}{4 \text{ hours}} = 90 \text{ tea crates/hour}
   \]

Thus, Eddie dumps tea at a rate of 90 tea crates per hour.

The final answer is \(\boxed{90}\)