Question 709523



a business trip of {{{d=203.5mil}}}


averaged {{{61mph}}} for the first part {{{d[1]}}}


and {{{57mph}}} for the second part {{{d[2]}}}


the trip took {{{t=3.5h}}}


{{{d[1]+d[2]=203.5mil}}}......eq. 1


{{{d[1]=61mph*t[1]}}} for the first part {{{d[1]}}}


{{{d[2]=57mph*t[2]}}} for the first part {{{d[1]}}}


{{{t[1]+t[2]=3.5 h}}}.............eq. 2

{{{d[1]=203.5mil-d[2]}}}......eq. 1a

{{{t[1]=3.5 h-t[2]}}}.............eq. 2a


{{{61mph*t[1]+57mph*t[2]=203.5mil}}}...substitute {{{t[1]}}}

{{{61mph*(3.5h-t[2])+57mph*t[2]=203.5mil}}}.....solve for {{{t[2]}}}

{{{213.5mil*-61mpht[2])+57mph*t[2]=203.5mil}}}

{{{(-61mph+57mph)t[2]=203.5mil-213.5mil}}}

{{{(-4mph)t[2]=-10mil}}}

{{{t[2]=-10mil/-4mph}}}

{{{highlight(t[2]=2.5h)}}}


then {{{t[1]=3.5 h-2.5h}}}...=>...{{{t[1]=hig1hlight(1h)}}}

go back to {{{d[1]=61mph*t[1]}}} and solve for {{{d[1]}}}

{{{d[1]=61mph*t[1]}}}

{{{d[1]=61mph*1h}}}

{{{highlight(d[1]=61mil)}}}

do same with {{{d[2]}}}

{{{d[2]=57mph*2.5h}}}

{{{highlight(d[2]=142.5mil)}}}