Math
posted by Ed .
My child came home with an assignment on line segments. one of the problems is rs=2x st=3x rt=25 Their teacher told them that the solution is 15. My question is how did they come to this answer ?

r, s, and t are points along a line. r and t are the end points. rs, st and rt are the disatnces between the points.
rs + st = rt = 25 = 3x + 2x = 5x
Therefore x = 5
In this case st = 15 and rs = 10. It is not clear what the question was asking for. Was it the length of st? 
no