Answer:
Thad deposited an amount of $11,241.58 about 27 years ago,
Step-by-step explanation:
About Duane:
The amount deposited by Duane = $15,000
Time interval = 27 years
Rate = 5.2%
Now, SIMPLE INTEREST Â = Â [tex]\frac{P \times R \times T}{100}[/tex]
[tex]\implies SI = \frac{15,000 \times 27 \times 5.2}{100} Â = 21,060[/tex]
So, the SI on 15,000 after 27 years = $21,060
Now, AMOUNT = PRINCIPAL + SI
             = 15,000 + 21,060 = $36,060
Hence, after 27 years, Duane's amount is equivalent to $36,060
Now, About Thad:
Let us assume amount deposited  = P
Rate = 6.2%
Time = 27 y
Now, [tex]SI = \frac{P \times 27 \times 6.2}{100} Â = 1.674 P[/tex]
So, the SI on 15,000 after 27 years = $1.674 P
Now, AMOUNT = PRINCIPAL + SI
    $36,060  = P +  1.674 P
   or, 2.624 P =  $36,060
⇒ P = 30,060/2.624 = 11,241.58
Hence, Thad deposited an amount of $11,241.58 about 27 years ago,