Farmers marked 45 cows and released them. The next day they counted 150 cows and 15 had marks. Find the best estimate for the cow population.
Well, for every 150 cows, 15 had marks. We can estimate or guess that since there were 45 cows marked, which was thrice the amount of cows marked in the sample population, multiply the total sample by 3. Answer is 450 cows