Discussion
Suppose that someone starts with a chain letter. Each person who receives the letter is asked to send it on to 4 other people. Some people do this, while some do not send any letter. How many people have seen the letter, including the first person, if no one receives more than one letter and if the chain letter ends after there have been 100 people who read it but did not send it out ? Also find how many people sent out the letter ?
Answer: C
Let s be the number of people who sent the letter. Each of them sent it to 4 others, so the number of people who received it is 4s. Counting the first person, the total who have seen the letter is 1 + 4s. Also, those who have seen it consist of the s senders and the 100 who did not send it.
\[ 1 + 4s = s + 100 \Rightarrow 3s = 99 \Rightarrow s = 33 \]
So 33 people sent out the letter and 1 + 4(33) = 133 people saw it. The other pairs, 122 and 22, 111 and 11, and 144 and 44, do not satisfy 1 + 4s = s + 100.
Post your comment
Please log in or register to post a comment.
Examination Categories
- SSC Exams
- Banking Exams
- Teaching Exams
- Civil Services Exams
- Railways Exams
- Engineering Recruitment Exams
- Defence Exams
- State Government Exams
- Police Exams
- Insurance Exams
- Nursing Exams
- Other Government Exams
- NRA CET
- PG Entrance Exams
- Campus Placement
- MBA Entrance Exams
- CUET and UG Entrance
- Judiciary Exams
- Regulatory Body Exams
- Software Development