A certain population declines by 4% each year. What is the percentage decline each month? (Round your answer to two decimal places.)
An investment declines in value by 5% each month. By what percentage does its value decline in a year? (Round your answer to two decimal places.)
1) Since there are 12 months in a year...
-4/12 will be -1/3% or -0.33 decrease each month
2) There are 12 months in a year....
-5*12=-60.
It declines by 60% or 0.6 each year.
I'm confused too... I'm so sorry about my incorrect answers. I will look at them again right now!
Okay. Don't trust me 100%, though. I'm a really rushed, angry elementary school kid... LOL!
One of the compound interest formula is: F = A(1 + x )t
where F = final amount
A = initial amount
x = interest rate, as a decimal
t = number of years
For this problem, if the inital population = A, then the final population will be 0.96A (because it decreased by 4%).
So: 0.96A = A(1 + x)12
Divide both sides by A: 0.96 = (1 + x)12
Find the 12th root of 0.96: 0.9966039468 = 1 + x
Subtract 1: x = -0.003396 (the '-' indicates that it is decreasing)
An investment declines in value by 5% each month. By what percentage does its value decline in a year? (Round your answer to two decimal places.)
Let A be the value of the investment at the beginning of the year
At the end of the year, the investment will be worth
A(.95)^12 ≈ .54036 A
So......the % decline in one year = 1 -.54036 ≈ 45.964% ≈ 45.96%