Hello,
We have to use this relation : [tex] \text{rating}=\log(\text{ratio}) [/tex]
He we have :
[tex] \log_{10}(x)=7.8\\\\\text{then }x=10^{\log_{10}(x)}\\\\\rightarrow x=10^{7.8}\\\\\rightarrow x=6.309\times 10^{7}\\\rightarrow x=6.31\times 10^{7} [/tex]
