SOLUTION: Sara wants to buy a house and needs $35,560 for a down payment. She currently has $28,000 in a savings account that earns 9% simple interest. How long must Sara keep the money in

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Question 1032549: Sara wants to buy a house and needs $35,560 for a down payment. She currently has $28,000 in a savings account that earns 9% simple interest. How long must Sara keep the money in the savings account in order to have enough for the down payment on the house?
Found 2 solutions by Boreal, MathTherapy:
Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
P=Po(1+.09)^t
35,560/28,000=1.09^t=1.27
ln of both sides
ln (1.27)=t*ln (1.09)
t=ln(1.27)/ln(1.09)=2.77 years

Answer by MathTherapy(10552) About Me  (Show Source):
You can put this solution on YOUR website!
Sara wants to buy a house and needs $35,560 for a down payment. She currently has $28,000 in a savings account that earns 9% simple interest. How long must Sara keep the money in the savings account in order to have enough for the down payment on the house?
SI = PTR

7,560 = 28,000 * T * .09

7,560 = 2,520T

T, or time = 

If the interest that’s earned each year is WITHDRAWN EVERY YEAR, right after being added to the account, then it’d be 3 years, since

at all times, only the $28,000 would be earning interest. Otherwise, it'd be COMPOUNDED, and time would be shorter, at 2.77 years. 



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