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.

Guest Dec 30, 2018

#1**+2 **

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

Melody Dec 30, 2018