A cell phone is on sale for $205 after a 20% off discount. What was the original price of the phone?
1 answer:
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Answer:
The compounded annually account will earn more interest over 10 years
Step-by-step explanation:
The rule of the simple interest is I = Prt, where
- P is the original value
- r is the rate in decimal
- t is the time
The rule of the compounded interest is A = P, where
- A is the new value
- P is the original value
- r is the rate in decimal
- n is the number of periods
- t is the time
The interest I = A - P
∵ Each account start with $200
∴ P = 200
∵ They have an interest rate of 5%
∴ r = 5% = 5 ÷ 100 = 0.05
∵ One account earns simple interest and the other is compounded
annually
∴ n = 1 ⇒ compounded annually
∵ The time is 10 years
∴ t = 10
→ Substitute these values in the two rules above
∵ I = 200(0.05)(10)
∴ I = 100
∴ The simple interest = $100
∵ I = A - P
∵ A = 200
∴ A = 325.7789254
∵ I = 325.7789254 - 200
∴ I = 125.7789254
∴ The compounded interest = $125.7789254
∵ The simple interest is $100
∵ The compounded interest is $125.7789254
∵ $125.7789254 > $100
∴ The compounded annually account will earn more interest
over 10 years