Kendra tracks the different species of birds they spot on their birdwatching trip. On Monday they visited 5 sites and saw an average of 7 birds at each site. On Tuesday, Kendra visited 5 sites and saw an average of 5 birds at each site. On Wednesday visited 10 sites and saw an average of 8 birds at each site. On average, how many different birds did Kendra see on each site?
On Monday Kendra saw 5 sites x 7 birds/site = 
<gadget id="calculator">5*7</gadget>
<output>35</output>
35 different birds.
On Tuesday Kendra saw 5 sites x 5 birds/site = 
<gadget id="calculator">5*5</gadget>
<output>25</output>
25 different birds.
On Wednesday Kendra saw 10 sites x 8 birds/site = 
<gadget id="calculator">10*8</gadget>
<output>80</output>
80 different birds.
In total Kendra saw 35 birds + 25 birds + 80 birds = 
<gadget id="calculator">35+25+80</gadget>
<output>140</output>
140 different birds.
In total Kendra visited 5 sites + 5 sites + 10 sites = 
<gadget id="calculator">5+5+10</gadget>
<output>20</output>
20 sites.
On average Kendra saw 140 birds / 20 sites = 
<gadget id="calculator">140/20</gadget>
<output>7</output>
7 different birds at each site.

<result>7</result>