80 increased by 25%, then decreased by 25% is

See below.

Step-by-step explanation:

Increases by 25% : - it is 80 * 1.25 = 100.

100 decreased by 25% = 100 * 0.75

= 75.

75

Step-by-step explanation:

We are given that 80 is increased by 25% and then decreased by 25% so we are to find the final value.

Increase of 25% in 80 = 25% of 80

= 25/100 * 80

= 20

So our new value after 25% increase = 80 + 20 = 100

Now this new value is decreased by 25% = (100 - 25) % of 100

= 75/100 * 100

= 75