Question

The amount of simple interest earned, n, varies jointly with the rate of interest, r, and the number of years, t. The simple interest earned is $18 when the rate of interest is 3% for 1.5 years. How much simple interest, in dollars, will be earned when r=4% and t=2 years?

Answer 1

The formula for finding simple interest earned is n = krt, where n is the interest earned, r is the rate of interest, t is the number of years, and k is the constant of variation. By plugging in the given values into the formula and solving for the constant of variation, we can find the interest earned when r = 4% and t = 2 years.

Step-by-step explanation:

Since the amount of simple interest earned varies jointly with the rate of interest and the number of years, we can use the formula:

n = krt

where n is the interest earned, r is the rate of interest, t is the number of years, and k is the constant of variation.

Given that n = $18, r = 0.03, and t = 1.5, we can plug these values into the formula and solve for k:

$18 = 0.03k(1.5)

k = $18 / (0.03 * 1.5) = $400

Now, we can use this value of k to find the interest earned when r = 0.04 and t = 2:

= $400 * 0.04 * 2 = $32

Therefore, the simple interest earned when r = 4% and t = 2 years is $32.