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An investment’s value is rising at the rate of 5% per year. The initial value of the investment is $20,000 in 2016.

Write the function that gives the value of the investment as a function of time in years after 2016.
Find the value of the investment in 2028
When will the value be $30,000?

User QMG
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1 Answer

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The formula, it would take approximately 8.30 years for the investment to reach $30,000.

The formula to calculate the value of the investment over time, given a yearly growth rate of 5%, would be:

V(t) be the value of the investment at year t after 2016.

r be the annual rate of increase (5% in this case).

V0 be the initial value of the investment ($20,000).

We know that the investment grows by a factor of 1+r each year. So:

V(t) = V0 * (1 + r)^t

Substituting the given values:

V(t) = 20000 * (1 + 0.05)^t

Value in 2028:

2028 is 12 years after 2016, so:

V(12) = 20000 * (1 + 0.05)^12

V(12) = 20000 * (1.05)^12

V(12) = 20000 * 1.795856

≈ $35917.12

To solve for the time it takes to reach $30,000 using the formula

t×ln(1+r)=ln( V(t)/ V_0):

Given V_0 =20000,V(t)=30000,r=0.05

t×ln(1+0.05)=ln( 30000/ 20000)

​t×ln(1.05)=ln(1.5)

Now, solve for t:

t= ln(1.5)/ ln(1.05)

t≈ 0.4055/ 0.0488

t≈8.30

Therefore, according to the formula, it would take approximately 8.30 years for the investment to reach $30,000.

User ChikabuZ
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