Question 954012
R=900
r=750
t, unknown time length going A to B.
k=1/3 hour, how much time less on returning, B to A
Question asks for t-1/3;
Understand that 20 minutes is {{{1/3}}} of an hour.



_________________speed__________time________distance
GOTO_____________r_______________t__________d
BACK_____________R_____________t-k________d


Basic uniform rates of travel fact, RT=D


EQUATIONS:
{{{system(rt=d,R(t-k)=d)}}}


{{{rt=R(t-k)}}}
{{{rt=Rt-Rk}}}
{{{Rt-rt=Rk}}}


{{{t=Rk/(R-r)}}}


What is really wanted, if keeping in symbols first, is
{{{t-k=(Rk)/(R-r)-k}}}
{{{highlight(t-k=highlight(r/(R-r)))}}}


Substitute the values to finish.