Answer:
3.2%
Explanation:
The computation of the annual rate of interest is shown below:
As we know that
Simple interest = Principal × rate of interest × time period
($1,857.60 - $1,800) = $1,800 × rate of interest × 1
$57.60 = $1,800 × rate of interest × 1
So, the rate of interest is
= $57.60 ÷ $1,800 × 100
= 3.2%
Hence, the rate of interest on annual basis is 3.2%