Iunderstand 560-500 over 500. but why is it multiplied by 100?

To make it a percent, because when you find the answer, it will be given in a decimal. And to make the decimal a percent you have to multiply it by 100%

109 trust me

step-by-step explanation:

it's equivalent, so we can say that its equal.

let's call the denominator x and the numerador is 18 less then denominator, x - 18.

multiply

2.x = 5.(x - 18)

2x = 5x - 90

90 = 5x - 2x

90 = 3x

x = 90/3

x = 30

so: