Solve for "years" (t)
A=P e^(rt)
A=1000
P=500
e=e
r=0.0462
Solve for t: use natural logarithms
(0.0462)t=in 2
t=15 years
<span>Confidence Interval = (p-E, p+E) = (0.71-0.025, 0.71+0.025) = (0.685, 0.735) </span>
Let x be the number of months.
The first plan is 15 dollars sign up fee and 38 dollars per month. So the equation is 38x + 15.
The second plan is 78 dollars as sign up fee and 31 dollars per month. So the equation is 31x + 78.
We need find when x has the same value in both equations, so we do their equality:
38x + 15 = 31x + 78
Let's subtract 15 from both sides
38x + 15 = 31x + 78
38x + 15 - 15 = 31x + 78 - 15
38x = 31x + 63
Now let's subtract 31x from both sides to have the variables on a side and the numbers on side:
38x = 31x + 63
38x - 31x = 31x - 31x + 63
7x = 63
Divide both sides by 7 to have the variable x on a side and its value on the other:
(7x)/7 = 63/7
x = 9
So at month 9, the 2 plans will cost the same.
Let's check our answers, and let y be the cost:
y = 38x + 15 = 38*9 + 15 = 357
y = 31x + 78 = 31*9 + 78 = 357
Our answer has been approved.
Hope this helps! :D
Alan is 14 years old
He is twice as old as James
then Alan is the elder brother
Alan is twice as old means his age is double the age of James
Alans age = 2 x james age
that means James must be half of Alans age
Alans age = 14 years
James age = 14 / 2 = 7 years
therefore James is 7 years old
So for 9, to graph all you need to do is start at the origin (0,0) and go up 4 and over (right) 1.
