You are given thirteen identical- looking balls and a two-sided scale. One of the balls is of a different weight, although you don't know whether it's lighter or heavier. How can you use just three weighings of the scale to determine the different ball?

Pet Owners According to the Humane Society, in 2015, 65% of U.S. households owned at least one pet, and 42% of households who did own pets owned at least two. The U.S. Census Bureau tells us that there were 117 million households in 2015. How many households owned at least two pets? Report your answer in millions rounded to two places.

:: 6.98 Translate to a proportion: 27 is 36% of what number?