Ravi has 5 friends.In how many ways can he invite one or more of them to a dinner?
option
i. 31
ii. 5^5
iii. 13
iv. 2^5

• When he want to call only one friend no of ways =5
  when he wants to call two frnds, no of ways he can call=5c2=10
  when he wants to call three frnds, no of ways he can call=5c3=10
  when he wants to call four frnds, no of ways he can call=5c4=5
  when he wants to call five frnds, no of ways he can call=5c5=1
  
  so totally he can call one or more frnds in (5+10+10+5+1)=31 ways.
  
  
  
• 11 years agoHelpfull: Yes(9) No(1)
• Here, for every friend Ravi has two options,
  
  Either inviting the friend or not inviting the friend
  
  So, for every friend there are two options, for five friends he has
  2*2*2*2*2 = 32 ways.
  
  But, in these 32 ways, we even considered the possibility of not inviting any of the five friends.
  That particular possibility should be deducted from the list.
  
  So, the answer will be 32 - 1 = 31
  Answer is 31
• 11 years agoHelpfull: Yes(5) No(0)
• : he may invite one or more friends by selecting either one or two or three or four or five friends out of five friends.
  Therefore, 1 friend can be selected out of 5 in 5c1 ways
  2 friend can be selected out of 5 in 5c2 ways
  3 friend can be selected out of 5 in 5c3 ways
  4 friend can be selected out of 5 in 5c4 ways
  5 friend can be selected out of 5 in 5c5 ways
  5c1+5c2+5c3+5c4+5c5=31
  
• 11 years agoHelpfull: Yes(4) No(0)
• ans:
  No of ways:-
  when he calls 1 friend = 5c1
  2 friends = 5c2
  3 friends = 5c3
  4 friends = 5c4
  5 friends = 5c5
  total no of ways=5c1+5c2+5c3+5c4+5c5
  =5 + 10 + 10 + 5 + 1
  =31
• 11 years agoHelpfull: Yes(2) No(0)
• When he want to call only one friend no of ways =5
  when he wants to call two frnds, no of ways he can call=2+2+1=3(taking 2members at a time.if only one person is left then treat that one as a new group)
  similarly
  
  when he wants to call three frnds, no of ways he can call=3+2=2
  when he wants to call four frnds, no of ways he can call=4+1=2
  when he wants to call five frnds, no of ways he can call=5=1
  
  so totally he can call one or more frnds in (5+3+2+2+1)=13 ways.
• 11 years agoHelpfull: Yes(1) No(1)
• i.31
  5C1+5C2+5C3+5C4+5C5=31
• 11 years agoHelpfull: Yes(0) No(0)
• total no.of ways-one way in which none are invited=(2^5)-1=31
  
• 11 years agoHelpfull: Yes(0) No(0)
• 2^5-1=31
• 11 years agoHelpfull: Yes(0) No(0)
• ans is 31. he can invite 1 person from persons in 5 ways as he can select 1 person from 5 person in 5 ways. similarly, he can invite/select 2 persons in 5c2 ways. in that manner, ans: 5c1+5c2+5c3+5c4+5c5=31.
• 11 years agoHelpfull: Yes(0) No(0)
• 5c1+5c2+5c3+5c4+5c5=(1+1)^5-1=31
• 11 years agoHelpfull: Yes(0) No(0)
• among 5 friends
  He want to call one friend it can be done in 5c1 ways = 5
  similarly he want to call two friends in 5c2=10 , three friends in 5c3=10 ,four friends in 5c4=5 ,five friends in 5c5 ways = 1 ,so total ways are (5+10+10+5+1="31" ways ).
• 11 years agoHelpfull: Yes(0) No(0)
• the ans is :
  5C1+5C2+5C3+5C4+5C5=31
• 10 years agoHelpfull: Yes(0) No(0)