Lord, we offer to You our class today. We pray that through Your Divine Guidance, we would learn how to listen attentively to the inputs of our teacher. May we appreciate his/her effort in imparting his/her knowledge to us. Amen!
Problem Solving: Permutations and Combinations Quarter 3 - Lesson 5
EXPLORATIONs Lock A Lock B Lock C permutations permutations combinations
illustrations
Example 1 . In how many ways can 5 bicycles be parked if there are 7 available parking spaces? permutations Solution: 7 P 5 = 2,520 The 5 bicycles can be parked in 7 available parking space in 2,520 ways.
Example 2 . How many ways can the letters of the word MATHEMATICIAN be arranged? distinguishable permutations Solution: = 129,729,600 There are 129,729,600 ways can the letters of MATHEMATICIAN be arranged. 13! 2! 3! 2! 2!
Example 3 . If the sections of Grade 10 class in BNHS must play with the other section in a basketball tournament, how many elimination games will there be? combinations Solution: = 120 There are 120 elimination games. 16 C 2
Example 4 . In a group of 6 boys and 4 girls, four children are to be selected. In how many ways can they be selected such that at least one boy should be there? combinations Solution: There are 209 ways can four children be selected. 4 boys : 6 C 4 3b & 1g : 6 C 3 4 C 1 2b & 2g : 6 C 2 4 C 2 1b & 3g : 6 C 1 4 C 3 = 15 = 80 = 90 = 24 = 209 10 C 4 – 1 = 209
Example 5 . (a) In how many ways can the 12 members of the Board of Directors (BOD) be chosen from 12 parent-nominees and 7 teacher-nominees if there must be 8 parents in the BOD? (b) after the 12 members are chosen, in how many ways can they elect among themselves the top 7 positions (president, vice-president, and others)? combinations and permutations Solution: (a) 12 C 8 7 C 4 = 17,325 (b) 12 P 7 = 3,991,680