There are 28 students in 3b, for math 18 students have an F. How many % is that?

Two variables, x and y, vary inversely, and x=12 when y=4. what is the value of y when x=3?

Out of $20$ creepy-crawly creatures in a room, $80\%$ are flies and $20\%$ are spiders. if $s\%$ of the total legs belong to spiders, what is $s$?

Atorch and a battery cost 2.50 altogether. the torch costs 1.50 more than the battery. what fraction of the total price is the torch? give your answer in its simplest form.