Two boxes are pulled to right by a force of 43.0N. The left box has a mass of 71.0kg and the right box has a mass of 35.0kg. Calculate the acceleration of the system

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:

rick would give her the best deal as he will charge $8.88 per hour