Answer:
76,800 subscribers :)
Step-by-step explanation:
Initially: 4,800
3 years: If the number of subscribers is doubling every 3 years, all you have to do is multiply it by 2.
4,800 · 2 = 9,600
So, after 3 years, they have 9,600 subscribers.
6 years: Now that the health blog has 9,600 subscribers, you need to multiply THAT number by 2.
9,600 · 2 = 19,200
Now the blog has 19,200 subscribers
9 years: Now, we just repeat what we've been doing for the other 6 years: multiply the blog's current subscriber count by 2.
19,200 · 2 = 38,400
12 years: Once more and we'll have our answer! Sub count is 38,400. Now double it.
38,400 · 2 = 76,800
Hope this helps! :)
