Answer:
-1/2
Step-by-step explanation:
To solve this we are going to use formula for the future value of an ordinary annuity:
where
is the future value
is the periodic payment
is the interest rate in decimal form
is the number of times the interest is compounded per year
is the number of years
We know from our problem that the periodic payment is $50 and the number of years is 3, so
and
. To convert the interest rate to decimal form, we are going to divide the rate by 100%
Since the interest is compounded monthly, it is compounded 12 times per year; therefore,
.
Lets replace the values in our formula:
We can conclude that after 3 years you will have $1909.08 in your account.
Answer:
48 cubic feet of mulch
Step-by-step explanation:
12 feet long x 4 feet wide x 1 foot deep of mulch= 48 cubic feet of mulch
So for this problem, we will be using the exponential equation format, which is y = ab^x. The a variable is the initial value, and the b variable is the growth/decay.
Since our touchscreen starts off at a value of 1200, that will be our a variable.
Since the touchscreen is decaying in value by 25%, subtract 0.25 (25% in decimal form) from 1 to get 0.75. 0.75 is going to be your b variable.
In this case, time is our independent variable. Since we want to know the value 3 years from now, 3 is the x variable.
Using our info above, we can solve for y, which is the cost after x years.
In context, after 3 years the touchscreen will only be worth $506.
Answer:
And rounded up we have that n=2663
Step-by-step explanation:
Previous concepts
A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".
The margin of error is the range of values below and above the sample statistic in a confidence interval.
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
The population proportion have the following distribution
Solution to the problem
In order to find the critical value we need to take in count that we are finding the interval for a proportion, so on this case we need to use the z distribution. Since our interval is at 99% of confidence, our significance level would be given by and . And the critical value would be given by:
The margin of error for the proportion interval is given by this formula:
(a)
And on this case we have that and we are interested in order to find the value of n, if we solve n from equation (a) we got:
(b)
We can assume an estimated proportion of since we don't have prior info provided. And replacing into equation (b) the values from part a we got:
And rounded up we have that n=2663