1
algebra

Worker A can do a job in 3 hours. Worker B can do it in 6 hours. If they work together, how long will it take?

A

9

B

4.5

C

2

D

3

Correct Answer: C

Choice Ahoice B is the correct answer.

  1. Rates: A = 1/31/3, B = 1/61/6.
  2. Equation: 13+16=1t\frac{1}{3} + \frac{1}{6} = \frac{1}{t}
  3. Common Denominator: 26+16=36=12\frac{2}{6} + \frac{1}{6} = \frac{3}{6} = \frac{1}{2}
  4. Solve: 12=1t→t=2\frac{1}{2} = \frac{1}{t} \rightarrow t = 2

Choice Ahoice C is incorrect because average of times is wrong.

Choice Ahoice D is incorrect because calculation error.

Choice Ahoice D is incorrect because calculation error.

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Linear Functions Set 32