Let s = the speed of the slower train in km/hrs+10 = the speed of the faster train in km/hrLet t = time in hrs for the slower train to go 160 kmt-5 = time in hrs for faster train to go 160 km---------------Slower train:(1) 160=s.t
Faster train:(2) 160=(s+10) .(t-.5)From (1)(1) t=160/s use the relations given in following screenshot and then use quadratic equation.
The reason I say this is because of the fact you can't go into retirement without knowing how much your going to get. You need to create a financial plan stating how much you will get and how much you have saved prior to this occurence.