Question

Solve the following variation problem.The interest on an investment varies directly as the rate of interest. If the interest is $45 when the interest rate is4%, find the interest when the rate is6.5%.What interest is $

Answer 1

we know that

A relationship between two variables, x, and y, represent a proportional variation if it can be expressed in the form

y=kx

Let

y -------> the interest

x ------> rate of interest

we have that

For y=$45, x=4%

Find the value of k (constant of proportionality)

k=y/x

k=45/4

k=11.25

so

the linear equation is

y=11.25x

find the interest when the rate is 6.5%.

so

For x=6.5%

substitute in the equation

y=11.25(6.5)

y=$73.13