Answer:
"85%" is the right answer.
Step-by-step explanation:
Given:
[tex]\mu = 70[/tex] (%)
[tex]\sigma = 5[/tex] (%)
As we know,
The 99.7% observation fall within the 3rd standard deviation, then
⇒ [tex](\mu \pm \sigma ) = (70-(3\times 5)) \ to \ (70+(3\times 5))[/tex]
[tex]=(70-15) \ to \ (70+15)[/tex]
[tex]=55 \ to \ 85[/tex] (%)
Thus the above is the correct solution.