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?
Thoughts? Step-by-step reasoning:
On Monday Kendra saw 5 sites x 7 birds / site = 35 different birds. On Tuesday Kendra saw 5 sites x 5 birds / site = 25 different birds. On Wednesday Kendra saw 10 sites x 8 birds / site = 80 different birds. In total Kendra saw 35 birds + 25 birds + 80 birds = 140 different birds. In total Kendra visited 5 sites + 5 sites + 10 sites = 20 sites. On average Kendra saw 140 birds / 20 sites = 7 different birds at each site.
Thus, the answer is 7.