Q. How long will it take $3,000 to grow to $10,000 if it is invested at 6% compounded monthly?□ years (Round to the nearest tenth of a year.)
Identify Variables: Identify the variables from the problem.Principal amount P = $3,000Future value A = $10,000Annual interest rate r = 6% or 0.06 (as a decimal)Compounded monthly means the number of compounding periods per year n = 12We need to find the time t in years.
Use Formula: Use the compound interest formula to set up the equation.The compound interest formula is A=P(1+r/n)(nt).Substitute the given values into the formula to get:$10,000 = $3,000(1+0.06/12)(12t).
Simplify Equation: Simplify the equation.$10,000=$3,000(1+0.005)12t$10,000=$3,000(1.005)12t
Isolate Exponential Part: Divide both sides of the equation by $3,000 to isolate the exponential part.$10,000/$3,000=(1.005)12t3.3333…=(1.005)12t
Take Natural Logarithm: Take the natural logarithm (ln) of both sides to solve for the exponent.ln(3.3333…)=ln((1.005)12t)ln(3.3333…)=12t⋅ln(1.005)
Solve for Exponent: Divide both sides by 12×ln(1.005) to solve for t. t=12×ln(1.005)ln(3.3333…)
Calculate Value of t: Calculate the value of t using a calculator.t≈(12×ln(1.005))ln(3.3333…)t≈(12×0.0049875621120890275)1.0986122886681098t≈0.059850745345068331.0986122886681098t≈18.354648862953
Convert to Years: Convert the time from months to years by dividing by 12.t≈18.354648862953/12t≈1.52955407191275Round to the nearest tenth of a year.t≈1.5 years