Diameter of a grain of sand = 2 x 10^{-4}
Diameter of the average cell in the human body = 1 x 10^{-5}
Difference of diameter of grain of sand and cell of human body
= 2 x 10^{-4} - 1 x 10^{-5}
= [tex] 2 * 10^{-4} - 1 * 10^{-5} = ( \frac{2* 10^{-4}}{10^{-5}} - \frac{1*10^{-5}}{10^{-5}} )*10^{-5}[/tex]
= [tex](2*10^{-4-(-5)} - 1*10^{-5-(-5)})*10^{-5}[/tex]
= [tex](2*10^{-4+5}-1*10^{-5+5})*10^-5= (2*10^{1}-1*10^{0})*10^{-5} [/tex]
= [tex](2*10 - 1*1) *10^{-5} = (20 - 1)*10^{-5} [/tex]
= [tex]19 * 10^{-5}[/tex]
= 19 × 10^{-5}
Hence, the diameter of a grain of sand is 19 × 10^{-5} longer than the diameter of the average cell of the human body.
