Applications 11: Exponential and Logarithmic Equations 1. Finance Sung Lee invests $5,000 at age 18. He hopes the investments will be worth $10,000 when he turns 25. If the interest is compounded continuously, approximately what rate of growth will he need to achieve his goal? Is that a reasonable expectation? Why or why not? 2. Sound The formula for measuring sound intensity in decibels D is defined by the 1D = 10log(+), where I is the intensity of the sound, in watts per -12 W square meter, and I = 10 is the lowest level of sound that the average person can hear. What is the intensity of a hair dryer that makes a sound of 90dB? equation m

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