Answer:
r=5%
New balance=$ 517.5
Step-by-step explanation:
We use the simple interest formula:
I=prt.
to determine the rate per annum of a principal of $450 that is invested for 3 years and earned an interest of $ 67.5
We substitute to get:
67.5=450×r×3
[tex]r = \frac{67.5}{3 \times 450} [/tex]
We simplify to get:
[tex]r = 0.05[/tex]
The rate of interest is 5%
The new balance is
Principal + Interest.
[tex] = 450 + 67.5[/tex]
[tex] = 517.5[/tex]
The new balance $517.5
