Question

Two numbers are respectively 30 percent and 40 percent less than a third number. What percent is the second of the first?

Answer 1

Let the third number = x
∴ First number = `x - (30x)/(100)`

= `(100x - 30x)/(100)`

= `(70x)/(100)`

= `(7x)/(10)`

Second number = `x - (40x)/(100)`

= `(100x -40x)/(100)`

= `(60x)/(100)`

= `(6x)/(10)`

∴ Required % = `((6x)/(10))/((7x)/(10))xx 100`

 = `(6x)/(10) xx (10)/(7x) xx 100`

= `(600)/(7)`

= 85`(5)/(7)%`