Question 105583
brooke walks 2 km/hr slower than her older sister Adrianna. If Brooke can walk 12 km in the same amount of time that Adrianne can walk 18 km, find their speeds.
:
Let x = walking speed of B
Then
(x+2) = walking speed of A
:
Write a time equation: Time = distance/speed
A's time = B's time
{{{18/((x+2))}}} = {{{12/x}}}
:
Cross multiply:
18x = 12(x+2)
:
18x = 12x + 24
:
18x - 12x = 24
:
6x = 24
:
x = {{{24/6}}}
x = 4 km/h is B's speed
then
4 + 2 = 6 km/h is A's speed
:
Check solutions by finding if they are equal times
18/6 = 3 hr
12/4 = 3 hr; confirms our solutions

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