What is the probability that Q and U sit together?
Consider the following for the next five (05) items that follow: Three boys P, Q, R and three girls S, T, U are to be arranged in a row for a group photograph.
- A. \frac{2}{3}
- B. \frac{1}{4}
- C. \frac{5}{6}
- D. \frac{1}{3} ✓
Correct Answer: D. \frac{1}{3}
Explanation
Treat Q and U as a single unit. There are now 5 units to arrange, which can be done in 5! = 120 ways. Q and U can swap places within their unit in 2! = 2 ways. Total favorable outcomes = 120 \times 2 = 240. The probability is \frac{240}{720} = \frac{1}{3}.
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