Please help me is due today and I am being timed

Valentina is subtracting from . she finds the lcd to be 15y2. what is valentina's next step?

What is the range? can’t seem to find it out

Suppose that prices of a gallon of milk at various stores in one town have a mean of $3.71 with a standard deviation of $0.10. using chebyshev's theorem, what is the minimum percentage of stores that sell a gallon of milk for between $3.41 and $4.01? round your answer to one decimal place.