Question 68763
His time for the 1st 100 miles is
{{{t = 100 / 40}}}
{{{t = 2.5}}} hrs
For the next 100 miles his time is
{{{t = 100 / 50}}}
{{{t = 2}}} hrs
His total distance travelled is 200 mi.
ave speed = toal distance / total time
{{{s[ave] = 200 / (2 + 2.5)}}}
{{{s[ave] = 200 / 4.5}}}
{{{s[ave] = 44.44}}} mi/hr answer
Note this is not the same as
{{{(40 + 50) / 2 = 45}}} mi/hr