Question 872170
Carlos walks around the track 10 times at a rate of x laps per hour.
 He runs around the track 8 times at a rate of 3x laps per hour.
 Write and solve an expression for the time it takes him to go 18 times around the track.
:
Write a time equation; time = dist/speed
:
Walk time + run time = total time
{{{10/x}}} + {{{8/(3x)}}} = 
find the common denominator (3x)
{{{((3(10) + 8))/(3x)}}} = {{{38/(3x)}}} time to go around 18 times