I think the first problem is asking how many times bigger the sound from the old muffler than the minimum intensity of sound a human can hear.
problem 2 is the same as problem 1 except it’s a new different muffler.
problem 3 is about how much percentage of sound has decreased from the old muffler to the new muffler.
hope it helps
Sophia Elahi RPC Blog 
I posted in the forum also
I think the first problem is asking how many times bigger the sound from the old muffler than the minimum intensity of sound a human can hear.
problem 2 is the same as problem 1 except it’s a new different muffler.
problem 3 is about how much percentage of sound has decreased from the old muffler to the new muffler.
hope it helps
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