Q. Suppose you have $9500 deposited at 2.75% compounded semiannually. About long will it take your balanc to increase to $10900 ?
Identify Formula: Identify the formula for compound interest.The formula for compound interest is A=P(1+r/n)(nt), where:A = the amount of money accumulated after n years, including interest.P = the principal amount (the initial amount of money).r = the annual interest rate (decimal).n = the number of times that interest is compounded per year.t = the time the money is invested for, in years.
Plug in Values: Plug in the known values into the formula.We know that:P=$9500A=$10900r=2.75% or 0.0275 (as a decimal)n=2 (since the interest is compounded semiannually)We need to find t.So, the equation becomes $10900=$9500(1+0.0275/2)2t.
Solve for t: Solve for t.First, divide both sides by $9500 to isolate the exponential part of the equation:$10900/$9500=(1+0.0275/2)2t1.14736842105=(1+0.01375)2t
Simplify Equation: Simplify the equation.1.14736842105=(1.01375)(2t)Now we need to take the logarithm of both sides to solve for t.
Apply Logarithm: Apply the logarithm to both sides.Using the property of logarithms that log(bx)=xlog(b), we can write:log(1.14736842105)=2t⋅log(1.01375)
Isolate t: Isolate t.Divide both sides by (2⋅log(1.01375)) to solve for t:t=(2⋅log(1.01375))log(1.14736842105)
Calculate t: Calculate the value of t.Using a calculator, we find:t≈log(1.14736842105)/(2×log(1.01375))t≈0.0602735772/(2×0.0059564723)t≈0.0602735772/0.0119129446t≈5.0607
Interpret Result: Interpret the result.Since t is the number of years and we have found that t≈5.0607, it will take approximately 5.0607 years for the balance to increase from $9500 to $10900 with an annual interest rate of 2.75% compounded semiannually.
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