Respuesta :
Answer:
$431
Step-by-step explanation:
Given parameters:
Principal  = $200
Time given for the amount to double  = 13yrs
Unknown:
Amount in the account after 15yrs = ?
Solution:
To solve this problem, we need to find the interest rate on this investment.
  I = [tex]\frac{PRT}{100}[/tex]
I = interest
P = principal
R = Rate
T = time
 Now,
 if the amount should double,
   Interest earned  = $200
So;
     200  = [tex]\frac{200 x R x 13}{100}[/tex] Â
     200  = 26 x R
      R = 7.7%
Now, in 15yrs, this amount will be;
 let us find the interest;
      I  = [tex]\frac{200 x 7.7 x 15}{100}[/tex] Â
      I = $231
The amount in the account will be:
 Amount  = Principal + Interest
 Amount = $200 + $231  = $431
Answer:
445
Step-by-step explanation:
y=a(2)t/d
​
a=200 d=13 t=15 Â d is the doubling time
y=200(2)15/13
y=445.012590439
y≈445