6% or 0.06 is the simple interest rate the bank pays him.
Explanation:
Sir Ving Spoon earned $5,436 on his $7,550 certificate of deposit.
From this given information,
It can be determined that the Principal amount is $7550 and the interest amount is $5436.
The CD is for 12 years. Therefore, the number of years is 12.
To find the interest rate (r) :
Using the simple interest formula,
Interest = P×r×t
where,
- P is the principal amount = $7550
- r is the rate of interest.
- t is the number of years = 12
⇒ 5436 = 7550 × r × 12
⇒ 5436 = 90600 × r
⇒ r = 5436 / 90600
⇒ r = 0.06
Multiply by 100 to represent in rate %
⇒ r = 0.06 × 100
⇒ r = 6%
∴ 6% or 0.06 is the simple interest rate the bank pays him.