Answer:
40 people came to the Center to hike
Step-by-step explanation:
30 people took classes
22 did bird watching
12 did both
to solve, take 12 and subtract it from each one:
⇒ 30 - 12 = 18
⇒ 22 - 12 = 10
18 people only took classes
10 people only did bird watching
12 people did both
18 + 10 + 12 = 40
