Question

4. The population of a place in a particular year
increased by 15 %. Next year it decreased by 15%.
Find the net increase or decrease per cent in the
initial population.​

Answer 1

Answer:

Let the initial population be x

Find the population after first year:

Increase = 15% of x = 0.15x

Population = x + 0.15x = 1.15x

Find the population after second year:

Decrease = 15% of 1.15x = 0.15(1.15x) = 0.1725x

Population = 1.15x - 0.1725x =  0.9775x

Find the net decrease:

net decrease = x - 0.9775x = 0.0225x

Find the percentage decrease:

Percentage decrease = (decrease ÷ original) x 100

Percentage decrease = (0.0225x ÷ x) x 100 = 2.25%

Answer: The population has decreased by 2.25%

Answer 2

Answer:

Increased=115

Decreased=115-15%of 115=115-17.25=97.75

Net decrese=100-97.75=2.25%

or

Let the initial population be 100

First year it increases by 100 of 15% = 100×15/100=15

=>100+15=115

Next year it decreases by 15% of 115

=115×15/100 =69/4=17.25 

=> 115-17.25 = 97.75

decrease=100-97.75=2.25

decrease % = (2.25/100)×100%=2.25%

Hope it helps u mark as brainliest plz