What is the CONCENTRATION

What is the concentration of the dye in a solution with a percent transmittance reading of 45.8% at 640 nm?

Not sure if you need this but
This is the data I got:
(Concentration ------> Absorbance) :
(0.00--->0.000)
(1.00--->0.102)
(2.00----->0.143)
(3.00----->0.278)
(4.00------>0.401)
(5.00------>0.451)

I have NO idea what to do? You don't have to even do it just explain HOW to do it :/ Thank you!

This one's going to require a few steps, but they aren't too bad. First, since your question deals with percent transmittance, we need to convert all of those absorbance values to transmittance.

Our equation is: transmittance = 10^(-absorbance)

In particular, the %transmittance for 3.00 is 10^-.278 = 52.7%
and, the %transmittance for 4.00 is 10^-.401 = 39.7%

Our value of 45.8% falls between these percentages, so we know our concentration is between 3.00 and 4.00. To figure out the right value, we need to interpolate as below:

right concentration = [(45.8 - 52.7) / (39.7 - 52.7)] * (4.00 - 3.00) + 3.00 = 3.53

Thus, our concentration is 3.53 in whatever units you are using.