Question 129781
Let {{{r}}} be his usual speed
{{{d = r*t}}}
{{{d = r*(14/3)}}}
{{{d = (r + 3)*(13/3)}}}
Set the {{{d}}}'s equal to eachother
{{{r*(14/3) = (r + 3)*(13/3)}}}
multiply each side by {{{3}}}
{{{14r = 13(r + 3)}}}
{{{14r = 13r + 39}}}
{{{r = 39}}}
His usual speed is 39 km/hr
check answer:
{{{d = r*(14/3)}}}
{{{d = 39*(14/3)}}}
{{{d = 182}}}
{{{d = (r + 3)*(13/3)}}}
{{{d = 42*(13/3)}}}
{{{d = 182}}}
OK