(a) To determine the insterest, use the following formula for simple interest:
I = P*r*t
where,
P: principal investment
r: rate
t: time
If the credit union charges simple interest, then each day has a daily rate of:
r = 6.5%/365 = 0.0178% = 0.0178/100 = 0.000178
Then, for 356 days, the interest owed is:
I = ($5100)(0.000178)(356)
I = $323.18
Hence, the interest owed after 356 days is $323.18
(b) If the print shop does not make any payment, the amount owed is:
$5,100 + $323.18 = $5423.18