Question 304549
Let {{{t}}} = his time walking uphill
The ratio (time walking uphill)/(time walking downhill) = {{{60/40}}}
t/(time walking downhill) = {{{3/2}}}
{{{(2/3)*t}}} = time walking downhill
For uphill:
{{{d = 2t}}}
For downhill:
{{{d = r[d]*(2/3)*t}}}
{{{r[d]*(2/3)*t = 2t}}}
{{{r[d] = 1/(1/3)}}}
{{{r[d] = 3}}} mi/hr
------------------
The average speed is (total distance)/(total time)
Total distance = {{{d + d = 2d}}}
The time for uphill = {{{t = d/2}}}
The time for downhill = {{{(2/3)*t = d/3}}}
{{{2d / (d/2 + d/3) = 2/(3/6 + 2/6)}}}
{{{2/(5/6) = 12/5}}}
{{{2.4}}} mi/hr