The annual interest rate of her investment would be = 4%
Calculation of annual interest rate
The principal amount invested= $500
The period of investment= 4years
The interest received= $80
The interest rate= ?
To calculate the interest rate use the formula,
SI = P×T×R/100
80 = 500 × 4 ×R/100
Make R the subject of formula,
R= 80 ×100/500×4
R= 8000/2000
R= 4%
Therefore, the annual interest rate of her investment would be = 4%.
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