Answer:
[tex]6.67\%[/tex]
Step-by-step explanation:
we know that
The simple interest formula is equal to
[tex]A=P(1+rt)[/tex]
where
A is the Final Investment Value
P is the Principal amount of money to be invested
r is the rate of interest
t is Number of Time Periods
in this problem we have
[tex]t=15\ years\\ P=\$x\\ A=\$2x\\r=?[/tex]
substitute in the formula above
[tex]\$2x=\$x(1+15r)[/tex]
simplify
[tex]2=(1+15r)[/tex]
[tex]15r=2-1[/tex]
[tex]r=1/15=0.0667[/tex]
convert to percentage
[tex]0.0667*100=6.67\%[/tex]
