# Logarithms

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1. Find the amount of time required for an investment to double at a rate of 12.3% if the interest is compounded continuously.

MY ANSWER: 5.635 yrs

2. Solve e^(0.2x) < 21.2 by using natural logarithms.

MY ANSWER: X<15.270

3. Convert log(base 5) 47 to a natural logarithm and evaluate.

My answer: 2.392

4. The pH of a water supply is 7.3. What is the concentration of hydrogen ions in the tested water?

I’m not sure but is it 5.012 x 10^-8

Check my answers?

• Logarithms -

All good!

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