Question

Please answer both a and b

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.a. What distance represents

3

billion​ years?

b. How far from the end of the timeline does written human history​ begin?

a.

3

billion years is represented by

nothing

meters

of the timeline.

​(Type an integer or decimal rounded to the nearest tenth as​ needed.)

Answer 1

Answer: (a) 3 billion years=7.8 m (rounded to nearest tenth)

(b) 0.0000222 meters ago (Negligible distance) from the end of the timeline to the human histoy bein.

Explanation: (a) since, the total lifetime of earth=4.5 billion=10 meter.

So, 1 billion on the meter scale will be =10/4.5   

So, 3.5 million on the meter scale=3.5*(10/4.5)=7.77 meter=7.8 meter (approx)

(b) Since, 1 billion=1000000 thousands

So, 1 thousand=    billions

so, 10 thousands= billions.

Now, since, the 1 billion on 10 meter scale=10/4.5 meters.

So, billion on 10 meter scale= meter.

i.e. The written human histroy begin at 0.0000222 meter ago. I.e Nothing meter ago. (Negligible) on the 10 meter scale.