# Pigeonhole Principle – 1

## 9 thoughts on “Pigeonhole Principle – 1”

1. How long I begged you to cover this topic, and now just I just reached home after my exam and see it now ðŸ˜›

Thankfully, no question were asked in my slot from this topic, and hopefully the remaining exams do ask from this topic now ðŸ˜€

2. Vaibhav, only once (that I know of) has CAT asked a tough question on this topic. With limited time before CAT-13, I had to prioritise… and from my past experiences I judged Geometry and Co-ordinate Geometry to be more crucial and hence covered what I could from those topics in the time available (and I suspect you would have encountered those topics liberally in your exam for sure) ðŸ™‚ How was the test?

regards
J

3. Section 1 was easy to moderate. Some absolute sitters. A couple of TSD and DI were very very easy. A bit easy for NMAT level as well !

Section 2 was very very tough. Except FIB and PJ, everything was tough. The RC’s and the LR sets were very time consuming and tricky. But that was the general consensus it seems, everyone is saying that in the last few slots section 2 was rather tough, but 1 was on the easier side.

4. jaspreet |

Sir i was studying pigeonhole principle and i tried forming one question.Can you please help me on this.Is this Q right? if yes what should be the ans according to you? acc. to my understanding should be 26.
let A = (1,4,7,…100).Let S be a subset of A such that any 3 elements of S will give sum 105,n.let n be the min. value of no. of elements in S..what is the value of n?

5. Afraid it doesn’t make sense – if any 3 numbers out of a group have to give the same total, that is only possible if every element is the same.

regards
J

6. harish |

Sir,
how n=10 is possible..
it can be n=75 also..na

• Can you guarantee that someone will get at least 75? I can guarantee someone will get at least 10. Read the question carefully.

regards
J

7. Hi J, could you please provide an approach to solve this question?

A is the set of the first 100 natural numbers. What is the minimum number of elements that should be picked from A to ensure that at least one pair of numbers whose difference is 10 is picked?

• I am guessing this should be 51.

regards
J