Answer: 0.54 centuries
Diameter of the Earth[tex]=1.27\times10^7 m[/tex]
The rate at which it is digged [tex]r=0.4 miles/day[/tex]
The number of centuries it would take to dig =Distance to be digged/ rate at which it is digged.
Distance to be digged = diameter of the Earth [tex]=1.27\times10^7 m=7891.41 miles[/tex] (because 1 m=0.00062 miles)
Number of days it would take to dig [tex]= \frac{7891.41 miles}{0.4 miles/day}=19728.525 days[/tex]
[tex]1 year =365 days[/tex]
[tex]1 century=100 years[/tex]
[tex]19728.525 days=54.05 years=0.54 centuries[/tex]
Therefore, it would take 0.54 centuries to dig through to China.
