Question 29973
Let the hours of running time at 6mph be x
Let the hours of running time at 8mph be y


x+y=3.5
y=3.5-x (subsitution)


Equation:
*[tex 6x+8y=26]--->subsitute:

*[tex 6x+8(3.5-x)=26]

*[tex 6x+28-8x=26]

*[tex -2x=-2]
*[tex x = 1]


y=3.5-1
y=2.5


<font color = red>Hence, she ran for 1 hour at 6mph and 2.5 hours at 8mph.</font>
Paul.