You have to solve here an equation.
Imagine a segment where x, y and z are located. We know that Y is between X and Z, but not exactly where. What is obvious though, is that, since Y is between X and Z, XY + YZ = XZ.
Since we have their values, we just have to solve an equation here :
(3x-4) + (2x+3) = 24
3x - 4 + 2x + 3 = 24
5x -1 = 24
5x = 25
x = 25/5 = 5
The numerical length of XY = 3*5 - 4 = 15 - 4 = 11
The numerical length of YZ = 2*5 + 3 = 10 + 3 = 13
And the numerical length of YZ = 24
Good luck
