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Select the correct answer. Victor and Dennis are weeding a garden. If Victor worked alone, it would take him 30 minutes. Working together, they would finish in 12 minutes. When x represents the number of minutes it would take Dennis working alone, this situation is represented by this equation: Working alone, how long would it take Dennis to weed the garden? A. 15 minutes B. 18 minutes C. 20 minutes D. The rational equation has no valid solutions.

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Answer:

C. 20 minutes

Step-by-step explanation:

If Victor (V) worked alone, it would take him 30 minutes.

30 * V = 1

V = 1 / 30

When x represents the number of minutes it would take Dennis (D) working alone,

x * D = 1

D = 1 / x

Working together, they would finish in 12 minutes

12 (V + D) = 1

12( 1/30  + 1/x) =1

1/30 + 1/x = 1/12

Multiply all through by x

x/30 + 1 = x/12

x/30 - x/12 = - 1

( 2x - 5x ) / 60 = - 1

- 3x / 60 = - 1

- 3x = -60

x = -60 / -3 = 20 minutes