To solve for the time it takes to travel a certain distance at a certain speed, use the formula,
time = distance / speed
Given that the entire journey takes four hours, add up the time it takes David to row upstream with that of him travelling downstream. This is mathematically represented as,
total time = time upstream + time downstream
4 = 3/(x - 1) + 3/(x +1)
Solving for x in the equation gives 2. Thus, David's speed in still water is 2 miles per hour.
x=2 is only solution while x=1 is extraneous solution
Option C is correct.
Step-by-step explanation:
We need to solve the equation and find values of x.
Solving:
Find the LCM of denominators x-1,x and x-1. The LCM is x(x-1)
Multiply the entire equation with x(x-1)
Now, factoring the term:
The values of x are x=1 and x=2
Checking for extraneous roots:
Extraneous roots: The root that is the solution of the equation but when we put it in the equation the answer turns out not to be right.
If we put x=1 in the equation, the denominator becomes zero i.e
which is not correct as in fraction anything divided by zero is undefined. So, x=1 is an extraneous solution.
If we put x=2 in the equation,
So, x=2 is only solution while x=1 is extraneous solution
Option C is correct.
Keywords: Solving Equations and checking extraneous solution
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Try 3 because 3 times 3 is. 9
(9+52) -3(6)x
(61)-3(6)x
61-3(6)x
61-18x
-18x+61
Answer: The phone company Splint has a monthly cellular plan where a customer pays a flat monthly fee and then a certain amount of money per minute used on the phone. If a customer uses 320 minutes, the monthly cost will be $132. If the customer uses 520 minutes, the monthly cost will be $202.
Step-by-step explanation: