Vroom! Vroom! Vroom!
Three persons \(X,Y,Z\) travel from point \(A\) to point \(B\). They leave point \(A\) at the same time and follow the same route. \(X\) rides a motorcycle at a speed of \(56 km/h\), \(Y\) walks at a speed of \(8 km/h\) and \(Z\) walks at a speed of \(7 km/h\).
At the beginning, \(X\) gives a lift to \(Y\) at \(A\) to travel a part of the journey and then comes back to pick up \(Z\). They all arrive at point \(B\) at the same time. Given that \(Y\) walks \(2.8\) km. The distance which \(Z\) walked is \(x\) km. Find \(10x\).