Question 963985
Another question of this same form was already answered.  Try generalizing, in case more of this
type are found.


___________________speed___________time__________distance
PART1_______________r______________t+k___________U
PART2_______________r_______________t____________V


Uniform Travel Rates Rule, RT=D for relating rate, time, distance.


Your example uses
UNKNOWNS:  r, t
KNOWNS:
k=1
U=450
V=300


The question is asking for the value or solution for t.


{{{system(r(t+k)=U,rt=V)}}}

{{{r=V/t}}}
-
Substitute that:
{{{(V/t)(t+k)=U}}}
{{{V+(Vk)/t=U}}}
{{{(Vk)/t=U-V}}}
{{{Vk=t(U-V)}}}
{{{highlight((Vk)/(U-V)=t)}}}----symbolic solution for time t.  This would be for part two of the trip.