How to write 16 as a fraction

What is the distance between the points (2 -3) and (-6 4) on the coordinate plane

According to modern science, earth is about 4.5 billion years old and written human history extends back about 10,000 years. suppose the entire history of earth is represented with a 10-meter-long timeline, with the birth of earth on one end and today at the other end.

How much dextrose 70% must be mixed with dextrose 5% to prepare 1,000 ml of dextrose 20%?