Question 167224
d=r*t  1st lap  rate of car is {{{r[1]= 30mph}}}
d=r*t  2nd lap  rate is unknown{{{r[2]= unknown}}}

{{{(r[1]+r[2])/2=60mph}}} or {{{r[1]+r[2]=120}}} {{{r[2]=120-r[1]}}}

{{{r[2]=120-30=90}}}

car has to travel at 90mph on 2nd lap in order to avg 60mph for both laps.