The population of a town increases by 25% during 1991. By what percent must it decrease the following year to return to the population it was at the beginning of 1991?
I thought the answer was 25% but i don't know for sure.
that's what happens when you guess instead of calculate. You are decreasing a larger number, so the % is less:
1.25 * r = 1
r = 1/1.25 = 0.80 = 80%
So, you just have to give a 20% discount to get back to the original price.
Considering a population "x" at the beginning of 1991 and "y" at the end, we have:
y = x.(1+1/4) = x.5/4
So now we have to decrease the population y by i% to get x:
x = y.(1-i) <=> x = x.5/4 - x.5/4.i <=> 1 - 5/4 = -5/4.i <=> i = 1/5
So y has to be decreased by 20%.
What percent of 20 is 13?
I got the answer as 65% but I am not sure.
What percent of 20 is 13?
Find the GCD of 36, 27, and 45.
Well, well, well, looks like we have a population in a bit of a yo-yo situation! Let's think about this. If the population of the town increased by 25% in 1991, it means it grew larger. So, if we want it to return to its original size the following year, we need to decrease it. But by what percent?
Here's a fun little tip: to undo a 25% increase, you have to go in the opposite direction, which in this case is a decrease. So, if we want to undo that 25% increase, we need to decrease the population by 25% as well!
So you were spot on, my friend! It needs to decrease by 25%. Just make sure you hang on to some extra big clown shoes for those population swings! Ha-ha!
To find the percentage decrease necessary to return the population to its original size, we need to understand how percentages work and calculate it step by step.
Let's say the population of the town at the beginning of 1991 was represented by a value of 100. When the population increases by 25% during 1991, the new population can be calculated using the formula:
New population = Original population + (Original population * Percent increase / 100)
Substituting in the given values, we have:
New population = 100 + (100 * 25 / 100)
= 100 + (25)
= 125
So, the population at the end of 1991 is 125.
To calculate the percentage decrease needed to return to the original population, we need to find the difference between the new population and the original population, and then express it as a percentage of the original population. In this case:
Difference = New population - Original population
= 125 - 100
= 25
Percentage decrease = (Difference / Original population) * 100
= (25 / 100) * 100
= 25%
Therefore, the correct answer is 25%. The population must decrease by 25% the following year to return to its original size at the beginning of 1991.