Jin subtracted 0.57 from .7 to get 0.13 is his model correct

Don't know how to find x given these segment lengths

Shannon mary and john earn a weekly allowance ahannon earns the amount that is 2/3 of what john earns mary earns an amount that is 1 2/3 of what johns earns 20 dollars a week who eaens the greatest allowance and who earns the least

Arectangular garden measures 5m by 7m. both dimensions are to be extended by the same amount so that the area of the garden is doubled. by how much should the dimensions increase, to the nearest tenth of a metre?