Question

a no. is increase by 10% and the increase no. is decreased by 10% .show that the net decrease is 1%

Answer 1

Solution :-

Let the required number be 100.

Then, according to the question.

⇒ Firstly, the number is increased by 10 %

⇒ 100 + (100*10)/100

⇒ 100 + 10

= 110

Secondly, it is decreased by 10 % 

⇒ 110 - (110*10)/100

⇒ 110 - 11

⇒ 99

Net increase or decrease percentage

= (Original Number - New Number)*100/100

⇒ (100 - 99)*100/100

⇒ (1*100)/100

⇒ 100/100

= 1 %

So, net decrease is 1 %.

Answer.

Answer 2

this question solve by two methods
first method-
in the pic

second method-

let the number= 100
it increases by 10%
so 100 + (100×10)/100
= 100 + 10
= 110

then it decreases by 10%
so 110-(110×10)/100
= 110 - 11
= 99

so 100-99 = 1