If humans originated in africa and migrated to other parts of the world, some time would be required for this to occur. at the modest rate of one kilometer per year, how many centuries would it take for humans originating in africa to travel to china, some 10,000 kilometers away?

The decibel level of sound is 50 db greater on a busy street than in a quiet room where the intensity of sound is watt/m2. the level of sound in the quiet room is db, and the intensity of sound in the busy street is watt/m2. use the formula , where is the sound level in decibels, i is the intensity of sound, and is the smallest sound intensity that can be heard by the human ear (roughly equal to watts/m2).

Julia is going for a walk through the neighborhood. what unit of measure is most appropriate to describe the distance she walks?

Jacks bank statement shows an account balance of -$25.50. which describes the magnitude, of size, of the debt in dollars