Step-by-step explanation:
Let x be the smaller than 4 ×[tex]10^{-2}[/tex].
To find, the number of times smaller is 2 × [tex]10^{-3}[/tex] than 4 × [tex]10^{-2}[/tex] = ?
∴ x = [tex]\dfrac{4\times 10^{-2}}{2\times 10^{-3}}[/tex]
= 2 × [tex]10^{-2}[/tex] × [tex]10^{3}[/tex]
Using the identity,
[tex]a^{m}=\dfrac{1}{a^{-m}}[/tex]
= 2 × [tex]10^{-2+3}[/tex]
Using the identity,
[tex]a^{m} \timesa^{n}=a^{m+n}[/tex]
= 2 × [tex]10^{1}[/tex]
= 2 × 10
= 20
Thus, the required "option A) 20" is correct.
