7 cm long stick cut in three pieces . length of each pieces are natural number. what is the probability of formating triangle from the three pieces of the stick .please write in details
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Question:
The 7 cm long stick cut in three pieces, length of each pieces are natural number. What is the probability of formating triangle from the three pieces of the stick.
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Solution:
Let, three pieces be a, b and c.
We know, a + b + c = 7 and a, b & c € N
Let [ ] represent a piece.
Number of ways possible for a + b + c = 7,
Here arranged doesn't matter it means
» (1, 3, 3) = (3, 3, 1) = (3, 1, 3)
[a] [b] [c] = (1, 1, 5) ; (1, 4, 2) ; (1, 3, 3) ; (2, 2, 3)
Now, n (S) = 4
Let A be the event of sides forming triangle,
Note:
For triangle
Bigger side < Sum of other two sides
» n (A) = 2
Probability of A = n (A)/n (S) = 2/4 = 0.5
Therefore, probability of forming the triangle is 0.5
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