Question

the price of an article has been reduced by 10%. By how much percent must the new price be increased to retain the original price? ​

Answer 1

let the original price is 100Rs

10% reduced means new price 90Rs

to increase 90Rs upto 100Rs -

[(100-90)/90 ] ×100 = (100/9)%

= 11 1/9 %

so 11 1/9 % must be increased to retain original price.

Method 2

original price 100

then 10% less price = 90

new price is 90 and this will be 100% value in itself.

so let x% is added in 100% to retain price

90(100+x) % = 100 ( original price)

100+x = 1000/9 ; x = (1000/9)-100

x= 100/9 = 11.11

so required % is 11 1/9 %