# Summation for Average Speed

How would I write a summation for the average speed of an object, given $10$ speeds (which were calculated $r=\frac{d}{t}$)? Would it be:

$$\sum_{i = 1}^{10} \frac{d_i}{t_i}$$

or am I wrong? I'm not sure about the subscript i's after distance and time, and if they are actually number sequences that I could use. Thanks.

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No. Generally average speed is defined as the total distance divided by the total time. That would be

$$\frac{\sum_{i = 1}^{10} d_i}{\sum_{j = 1}^{10} t_j}$$

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