Seven sticks with lengths 2, 3, 5, 7, 11, 13 and 17 inches are placed in a box. Three of the sticks are randomly selected. What is the probability that a triangle can be formed by joining the endpoints of the sticks? Express your answer as a common fraction.
+118690 Seven sticks with lengths 2, 3, 5, 7, 11, 13 and 17 inches are placed in a box. Three of the sticks are randomly selected. What is the probability that a triangle can be formed by joining the endpoints of the sticks? Express your answer as a common fraction.
17,13, and 5 or 7 or 11 (3)
17, 11, and 7 (1)
13, 11, and 3,5,7 (3)
13, 7, and none
11, 7 and 5 (1)
7, 5, and 3 (1)
5, 3, and none
equals 9 favourable outcomes (you need to check)
Can you see how I have done this? What needs to happen for three lengths be able to form a triangle?
7C3=35
Probability = 9/35
