SOLUTION: Please help me with this problem. Kim decides to run 2 Km in to the local gym She runs the first x km at 8km/hr, then walks the rest at 4km/hr Altogether the journey takes 2

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Question 274878: Please help me with this problem.
Kim decides to run 2 Km in to the local gym
She runs the first x km at 8km/hr, then walks the rest at 4km/hr
Altogether the journey takes 20 minutes
Form and solve an equation to find the value of x
Answer by ankor@dixie-net.com(22740) About Me  (Show Source):
You can put this solution on YOUR website!
Kim decides to run 2 Km in to the local gym
She runs the first x km at 8km/hr, then walks the rest at 4km/hr
Altogether the journey takes 20 minutes
Form and solve an equation to find the value of x
:
change 20 min to 1%2F3hr
x = dist ran (given)
Then
(2-x) = dist walked
:
Write a time equation, time = dist/speed
:
Run time + walk time = 1/3 hr
x%2F8 + %28%282-x%29%29%2F4 = 1%2F3
Multiply by 24 to rid us of those denominators, results
3x + 6(2-x) = 8
:
3x + 12 - 6x = 8
:
3x - 6x = 8 - 12
:
-3x = -4
x = 4%2F3 or 11%2F3 km ran
:
:
Is this true, walk dist = 2/3 km, find the times using decimals
1.33/8 + .67/4 =
.166 + .1675 = .333 hr, which is 20 min