"ball goes in (thwack) to mitt,/ and goes out (thwack) back to mitt." this is an example of which sound device?

While there are many different sound devices that can be used in poetry, such as near rhyme (sounds are similar but not exact), alliteration (same beginning sounds), this one is onomatopoeia.  Onomatopoeia is using words to suggest a sound.  This can also be words like whispering, sizzle, thump, clang, etc.  Using onomatopoeia allows you to imagine what it would sound like if you were present (this is part of imagery).

for this case, we must find the number of deaths per day of the year 2015, in automobile accidents, knowing that 32,400 people died.

knowing that the year 2015 had 365 days we have the following division:

where "x" represents the number of deaths per day.

rounding off we have:

approximately, 89 people per day died in 2015

answer:

89 people per day

answer: the sentence in the text that contains both the topic and the author's single most important idea about the topic

explanation: aww pineapple so adorable