document.write( "Question 300316: Use the formula N = Iekt, where N is the number of items in terms of the initial population I, at time t, and k is the growth constant equal to the percent of growth per unit of time. There are currently 63 million cars in a certain country, decreasing by 6.9% annually. How many years will it take for this country to have 33 million cars? Round to the nearest year. \n" ); document.write( "

Algebra.Com's Answer #215526 by stanbon(75887) $\"\"$ $\"About$

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Use the formula N = Iekt, where N is the number of items in terms of the initial population I, at time t, and k is the growth constant equal to the percent of growth per unit of time. There are currently 63 million cars in a certain country, decreasing by 6.9% annually. How many years will it take for this country to have 33 million cars? Round to the nearest year.
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\n" ); document.write( "N = I*e^(kt)
\n" ); document.write( "---
\n" ); document.write( "Solve for \"t\" if I = 63 million, N = 33x10^6 and k = -0.069
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\n" ); document.write( "33 = 63*e^(-0.069t)
\n" ); document.write( "---
\n" ); document.write( "e^(-0.069t) = 11/21
\n" ); document.write( "---
\n" ); document.write( "Take the natural log of both sides to get:
\n" ); document.write( "-0.069t = ln(11/21)
\n" ); document.write( "t = 9.37 years
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\n" ); document.write( "Cheers,
\n" ); document.write( "Stan H.
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