How does LRV of a color relate to the amount of light that the color absorbs? (Pls helo)

Rate law for this reaction israte of the reaction = k[a]²[b].second order in a  means concentration of a in power of two, and  first order in b means concentration of b in power of one.

Radon-222 or rn-222 has a half-life of 3.82 days. to determine the fraction of an original sample of rn-222 that remains unchanged after 7.646 days, we calculate the amount of rn-222 remaining after 7.646 days and divide it with the original amount. using 1 gram as a basis and using half-life calculation methods, we can determine that  0.249 or 0.25  grams of rn-222 will remain, and thus the fraction remaining is 0.25 or 1/4.