In each of three boxes are four straws with integer lengths cm, cm, cm, and cm. A straw is randomly selected from each box. What is the probability that a triangle can be formed with the three straws chosen?
Could anyone also add an explanation with their answer? Thanks!
Could anyone also add an explanation with their answer?
The sum of any two sides of a triangle must be greater than its third side.
That's the explanation. The length of the straws wasn't visible in the post.
OK corrected version:
In each of three boxes are four straws with integer lengths 1 cm, 2 cm, 3 cm, and 4 cm. A straw is randomly selected from each box. What is the probability that a triangle can be formed with the three straws chosen?
Could anyone also add an explanation with their answer? Thanks!
Here is an explanation of the answer:
We can't form a triangle if any of the straws have length 1, so we need to consider the cases where all three straws have length 2, 2 and 3, or 3 and 4.
Case 1: All three straws have length 2. There are (34)=4 ways to choose which straws to select, so the probability of this case is 4/4^3=1/64
Case 2: Two straws have length 2 and one has length 3. There are (24)=6 ways to choose which straws to select, so the probability of this case is 6/4^3=3/64.
Case 3: One straw has length 2 and the other two have length 3. There are (14)=4 ways to choose which straw has length 2, so the probability of this case is 4/4^3=1/64.
The total probability is then 1/64+3/64+1/64=5/64.