Plz . tell this question...

Dear student
Since you have not mentioned the question number so doing as per my knowledge .
$$\begin{gathered} 6. \\ {2}^{\mathrm{n}-7}\times 5^{\mathrm{n}-4}=1250 \\ {2}^{\mathrm{n}-7}\times 5^{\mathrm{n}-4}=2^1\times 5^4 \\ \mathrm{Since} \mathrm{bases} \mathrm{are} \mathrm{same} \mathrm{so} \mathrm{comparing} \mathrm{powers} \mathrm{we} \mathrm{get} \\ \mathrm{n}-7=1 \mathrm{and} \mathrm{n}-4=4 \\ \mathrm{n}=8 \mathrm{and} \mathrm{n}=8 \\ \mathrm{So}, \mathrm{n}=8 \end{gathered}$$
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