Question 5492
his walking rate is 1/4 the distance every hour
his riding rate is the whole distance every hour
Let x=riding rate
let {{{x/4}}} = walking rate
riding rate is 6kmh faster, so
{{{x=x/4+6}}}
Multiply through by 4 to clear the denominator:
{{{4x=x+24}}}
subtract x from both sides:
{{{3x=24}}}
divide both sides by 3:
{{{x=8}}}
so he rides at 8 km per hour