Question

1. The price of an article is cut by 20%. To restore
it to its original price, the new price must be
increased by what percent?​

Answer 1

let the number be 100.

it is decreased by 20% = 100-(20/100×100)

= 80

let the increase % be 'x'

80+(x/100×80)= 90

80+80x/100

80x/100= 100-80

x= 20×100/80

x= 25

so,it will increase 25% .