This is a question that would have literally have taken two seconds to look up on google but the answer is 1.88 years.
-- Equations #2 and #6 are both the same equation,
and are both correct.
-- If you divide each side by 'wavelength', you get Equation #4,
which is also correct.
-- If you divide each side by 'frequency', you get Equation #3,
which is also correct.
With some work, you can rearrange this one and use it to calculate
frequency.
Summary:
-- Equations #2, #3, #4, and #6 are all correct statements,
and can be used to find frequency.
-- Equations #1 and #5 are incorrect statements.
The steps in order to calculate the mass of a given volume of water is to use density. <span>Density is a physical
property of a substance that represents the mass of that substance per unit
volume. It is a property that can be used to describe a substance. Density slightly varies with changes in temperature so that it is important to determine the temperature.</span>