Name: Navi

Who is asking: Student Level: Secondary

Children usually attend birthday parties where a thank you gift is given to the children who attent the party. a family likes to hand out books at thank-you gifts.

(a) One child invited to the party is given 2 books as gift. if there was 15 different books to choose from, how many diffrent gifts were possible?

Answeer: I did this way 15C2=105

(b) if the 15 books consisted of 8 nonfiction and 7 fiction, how many diffrent gifts were possible if at least 1 of 2 books were fiction?

15C7/15C8=41409225 please help me out with this question with all part B

Hi Navi,

You have 8 N's (non-fiction) and 7 F's (fiction). You must not pick both books from the N's (which could be done on 8C2 = 28 ways). You're 105 choices from part A included the possibility of two choices from the N's, thus the total number of selections including 1 or 2 F's is 105 - 28 = 77.

There is another, direct, approach to the poblem; can you see it?


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