Answer:
To earn $10 in 1st month, the principal must be $4,000.
No, the poster cannot claim that "Open an account of $2 comma 500 and earn at least $10 interest in 1 month!".
Step-by-step explanation:
We have been given that a bank manager wants to encourage new customers to open accounts with principals of at least $2,500. He decides to make a poster advertising a simple interest rate of 3%. We are asked to find the principal to advertise that one can earn $10 the first month.
We will use simple interest formula to solve our given problem.
, where,
I = Amount of interest,
P = Principal amount,
r = Annual interest rate in decimal form,
t = Time in years.

1 month will be equal to
.




Therefore, to earn $10 in 1st month, the principal must be $4,000.
Now, we will check if an account of $2,500 can earn at least $10 interest in 1 month.


Since the account earns an amount of $6.25 in one month, therefore, the poster is not true.