Final answer:
Miranda needs to put approximately $13,660.27 in the bank now.
Step-by-step explanation:
To find out how much money Miranda needs to put in the bank now to have $20,000 in four years with a 10 percent interest rate, we can use the formula for compound interest.
The formula for compound interest is: A = P(1+r/n)^(n*t), where A is the future amount, P is the principal amount (the initial amount), r is the interest rate, n is the number of times the interest is compounded per year, and t is the number of years.
In this case, the future amount is $20,000, the interest rate is 10 percent or 0.10, and the number of years is 4.
Substituting these values into the formula, we get: 20,000 = P(1+0.10/1)^(1*4)
Simplifying the equation, we get: 20,000 = P(1.10)^4
Dividing both sides of the equation by (1.10)^4, we get: P = 20,000 / (1.10)^4
Using a calculator, we find that P is approximately $13,660.27.