Answer: you put 9.655 in the account when you opened it
Step-by-step explanation:
The formula for determining simple interest is expressed as
I = PRT/100
Where
I represents interest paid on the amount of money deposited.
P represents the principal or amount of money deposited.
R represents interest rate on the deposit.
T represents the duration of the deposit in years.
From the information given,
Amount earned = 9.80
I = 9.8 - P
R = 6%
T = 3 months. There are 12 months in a year. Converting 3 months to year, it becomes 3/12 = 0.25 year
Therefore
9.8 - P = (P × 6 × 0.25)/100
9.8 - P = 0.015P
0.015P + P = 9.8
1.015P = 9.8
P = 9.8/1.015
P = 9.655