By David Pleacher
Question: Does a pound of gold or a pound of feathers weight more?
Answer: The feathers. A pound of feathers is measured in avoirdupois weight, in which one pound equals 16 ounces. Precious metals are measured in troy weight, in which one pound equals 12 ounces.
However, the ounces are not measured in the same way. In avoirdupois weight, one ounce = 437.5 grains. In troy weight, one ounce = 480 grains.
So, one pound of feathers weighs (16)x(437.5 grains) = 7,000 grains. One pound of gold weighs (12)x(480 grains) = 5,760 grains.
Question: When Tommy was 10 years old his sister Suzy was half his age. Now that Tommy is 50 years old how old is his sister Suzy?
Answer: 45 years old. Suzy was 5 when Tommy was 10 so she is 5 years younger.