A bag contains 5 balls which are numbered from 1 to 5. Two balls are drawn without replacement from this. Find the expectation of the sum of the numbers on these balls. (
Answers
The bag contains 5 balls numbered from 1 to 5. Two balls are drawn without replacement the possibilities are many.
the pair of numbers and the order of numbers on the ball can be,
1 & 2=1+2=3
1&3=1+3=4
1 & 4=1+4=5
, 1 & 5=1+5=6
2&3=2+3=5
2&4=2+4=6
2&5=2+5=7
3&4=3+4=7
3&5=3+5=8
4&5=4+5=9
and all these can also be in reverse order.
the sum of these numbers can be, 3,4,5,67,8 and 9
these are the expected sum of the numbers on these balls.
Answer
The bag contains 5 balls numbered from 1 to 5. Two balls are drawn without replacement the possibilities are many.
the pair of numbers and the order of numbers on the ball can be,
1 & 2, 1&3, 1 & 4, 1 & 5, 2&3,2&4, 2&5, 3&4, 3&5, 4&5 and all these can be in reverse order.
the sum of these numbers can be, 3,4,5,67,8 and 9
these are the expectation of the sum of the numbers on these balls.