Question 166929
Let x = time of the first lap
Let y = time of the second lap

Total time is 99 then x+y=99

 he ran the first lap at 8.5 m/s and the second at 8.0 m/s? 

distance of the first lap = distance of the second lap

then  8.5x=8y

so system is

{{{x+y=99}}}
{{{8.5x=8y}}}

{{{y=99-x}}}
then

{{{8.5x = 8(99-x)}}}

{{{8.5x=792-8x}}}

{{{16.5x=792}}}

{{{x=792/16.5=48}}} and {{{y=51}}}