I know the 1st and last one but i’m not sure on the rest sorry :(
Let's write it down:
<span>"60 is 75% of s" means:
60=75%*s
75% is

, (percent just means "out of 100" so we just divide it by 100) so we can also write:
60=</span><span>

s
now, let's multiply both sides by 4:
240=3s
and divide by 3:
80=s
So we have the result that the original value, s, is 80!
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