I might have did mistake with calculations but this is how you should do.
Answer:
1/4 of the original
Explanation:
That would be TWO half lives:
1/2 * 1/2 = 1/4 <======= 1/4 would be left
On an approximate scale, A child breaths 20 times a minute as compared to only 12 to 16 in resting phase of an Adult.
So, In 60 minutes (1 hour), They breathe = 20 * 60 = 1200
In 24 hours (1 day), They breathe = 1200 * 24 = 28,800
In short, Your Answer would be: 28,800
Hope this helps!