Answer: 286 minutes
Step-by-step explanation:
x : # of months that has gone by
0.24x : cost of the 24 cent plan after "x" minutes
39.95 + 0.10x : cost of the 10 cent plan after "x" minutes
1. 39.95 + 0.10x > 0.24x
2. 39.95 > 0.24x - 0.10x
3. 39.95 > 0.14x
4. 285.36 > x
x must be AT LEAST 286 minutes for plan #2 (39.95 + 0.10x) to be a better deal
Answer:
The value of first coin will be $151.51 more than second coin in 15 years.
Step-by-step explanation:
You have just purchased two coins at a price of $670 each.
You believe that first coin's value will increase at a rate of 7.1% and second coin's value 6.5% per year.
We have to calculate the first coin's value after 15 years by using the formula

Where A = Future value
P = Present value
r = rate of interest
n = time in years
Now we put the values



A = (670)(2.797964)
A = 1874.635622 ≈ $1874.64
Now we will calculate the value of second coin.



A = 670 × 2.571841
A = $1723.13
The difference of the value after 15 years = 1874.64 - 1723.13 = $151.51
The value of first coin will be $151.51 more than second coin in 15 years.