It takes 3 years for the balance of account to be $ 221
Solution:
From given information,
Principal = $ 200
Rate of interest = 3.5 %
Amount after "n" years = $ 221
To find: number of years
In simple Interest,
Simple interest = amount earned - principal
Simple interest = 221 - 200 = 21
Thus simple interest earned is $ 21
The formula for simple interest is given as:
[tex]simple\ interest = \frac{ p \times n \times r}{100}[/tex]
Where,
p is the principal
n is the number of years
r is the rate of interest per annum
Substituting the given values in formula,
[tex]21 = \frac{200 \times n \times 3.5}{100}\\\\21 = 2n \times 3.5\\\\n = \frac{21}{7}\\\\n = 3[/tex]
Thus it takes 3 years for the balance of account to be $ 221