Given:
Principal = $1290
Rate of simple interest = 4%
Time = 9 months
To find:
The interest and total saving in the account altogether.
Solution:
The formula for simple interest is
[tex]I=\dfrac{P\times r\times t}{100}[/tex] ...(i)
where, P is principal, r is rate of interest and t is time in years.
We know that,
[tex]12\ months=1\ year[/tex]
[tex]1\ month=\dfrac{1}{12}\ year[/tex]
[tex]9\ months=\dfrac{9}{12}\ year[/tex]
[tex]9\ months=0.75\ year[/tex]
Putting P=1290, r=4 and t=0.75 in (i), we get
[tex]I=\dfrac{1290\times 4\times 0.75}{100}[/tex]
[tex]I=\dfrac{3870}{100}[/tex]
[tex]I=38.70[/tex]
So, the simple interest is $38.70.
Total savings is
[tex]1290+38.70=1328.70[/tex]
Therefore, the total amount in the account altogether is $1328.70.
