If we let x be the amount of time, in hours, it will take for Darrel to catch up to the coyote, then we can figure this out.
Because the distance Darrel travels is defined as the length of time Darrel travels (x) and Darrel's speed (20mph), or the expression 2*x.
And the distance the coyote travels is defined as the length of time the coyote travels (x+1 hour) and the coyote's speed (15 mph), or the expression (x+1)*1.
And since the distance Darrel and the coyote travel is the same, then 2*x=(x+1)*1
Simplifying the expression, we get 2*x=x+1.
If we subtract 1 x from each side, we get x=1, the amount of time in hours.
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