SOLUTION: Emily is walking a trail. After walking k percent of the length of the trail. she has 10 km left to go. Which of the following represents the length of the trail? A) 10(100-k

Algebra ->  Expressions -> SOLUTION: Emily is walking a trail. After walking k percent of the length of the trail. she has 10 km left to go. Which of the following represents the length of the trail? A) 10(100-k      Log On


   



Question 1043631: Emily is walking a trail. After walking k percent of the length of the trail. she has 10 km left to go. Which of the following represents the length of the trail?
A) 10(100-k)
B) (100-k)/10
C) (10k)/(100-k)
D) 1000/(100-k)

Found 2 solutions by KMST, Boreal:
Answer by KMST(5328) About Me  (Show Source):
You can put this solution on YOUR website!
k= the length of the trail that Emily has walked (as percent of the total trail
100-k= the length of the trail that Emily has left to go (as percent of the total trail
100 = the length of the trail (as percent of the total trail)
10= the length of the trail that Emily has left to go (in km)
L= the length of the trail (in km)

The ratios of total distance to distance left to go are
L%2F10 and 100%2F%28100-k%29 .
Those expressions are the same ratio/fraction, calculated using different units, so
L%2F10=100%2F%28100-k%29---->L=10%28100%2F%28100-k%29%29---->L=highlight%281000%2F%28100-k%29%29
If you are typing on one line, you would write it as L=%221000+%2F+%28+100+-+k+%29%22 .

Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
The trail is x km long
at kx, k <1, there is 10 km left, so x-kx=10.
x(1-k)=10.
x=10/(1-k)
Because this is per cent for k, everything has to be multiplied by 100.
1000/(100-k) would be the answer.
D
Check
Suppose the trail is 25 km long, and she has 10 km left. She has walked 60 per cent of the trail
1000/(100-60)=1000/40=25 km.
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If she had walked 20% of the trail and had 10 km left
1000/(100-20)=12.5 km. That would mean she had walked 2.5 km (1/5 of 12.5 or 20%) and had 10 km left.