Question

4 boys and 3 girls stand in queue for an interview the probability that they stand in alternate position

Answer 1

Answer:

1

-------

35

Explanation:

Total number of possible arrangements for 4 boys and 3 girls in a queue = 7!

When they occupy alternate position the arrangement would be like

B G B G B G B

Thus, total number of possible arrangements

1. For boys = 4×3×2 and for girls = 3×2

Therefore, Required probability

= 4×3×2×3×2

---------------------

7!

= 4×3×2×3×2. 1

--------------------- = --------

7×6×5×4×3×2. 35

Answer 2

The probability that they stand in alternate position is = 1/35

Step by Step Explanation

The total number of possible arrangements for 4 boy and 3 girls in a queue = 7!

Occupying alternate positions, the arrangement would be BGBGBGB.

The number of favourable arrangements:

For boys = 4 x 3 x 2

For Girls = 3 x 2

Probability = Number of favourable outcomes/Total possible outcomes

∴ Required probability =  4 x 3 x 2 x 3 x 2 / 7!

= (4 x 3 x 2 x 3 x 2) / (7 x 6 x 5 x 4 x 3 x 2) = 1/35

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