Answer :
Remember the formula for simple interest (not compunded) is:
[tex]I=P\times R\times T[/tex]Where:
• P = Initial amount
,• R = Interest rate
,• T = Number of periods (years in this case)
The interest for 1 year is:
[tex]I=90\times0.1\times1=9[/tex]The total amount in the acount after one year would be $99