Question

Your older and wiser sibling has offered to loan you some much needed money to help cover textbook expenses this semester. Since you are their favorite your sibling will only charge you 1.25% per year in SIMPLE interest. If you were to make no repayments, how many years would it take to double your debt?

Answer 1

80 years

Step-by-step explanation:

Data provided in the question:

Simple interest rate charged = 1.25% = 0.0125

Now,

Let principal amount be '$x'

we know, Simple interest = Principal × Interest Rate × Time

Since the debt is doubled this means the interest is equal to the principal amount

Therefore,

$x = $x × 0.0125 × Time

or

1 = 0.0125 × Time

or

Time = 1 ÷ 0.0125

or

Time = 80 years