Question

The value of ${\log }_{3}5\times {\log }_{25}9$ is:

• A. $0$
• B. $1$
• C. $2$
• D. $4$

Answer 1

Answer: (B)

$1$

${\log }_{3}5\times {\log }_{25}9$

Using base change formula, we get

${\log }_{3}5\times {\log }_{25}9$

$=\frac{\log 5}{\log 3}\times \frac{\log 9}{\log 25}=\frac{\log 5}{\log 3}\times \frac{2\log 3}{2\log 5}$

$=1$