Given:
- 15 identical balloons.
- 6 identical pencils.
- 3 identical erasers.
- 3 children.
Each child requires a minimum of 4 balloons and 1 pencil. We will first allocate these minimums.
Each of the 3 children receives 4 balloons, totaling \(3 \times 4 = 12\) balloons. This leaves \(15 - 12 = 3\) balloons remaining for further distribution.
To find the number of ways to distribute \(n\) identical objects among \(r\) recipients, we use the stars and bars formula: \(\binom{n+r-1}{r-1}\).
For the remaining 3 balloons (\(n=3\)) and 3 children (\(r=3\)):
Number of ways to distribute remaining balloons: \(\binom{3+3-1}{3-1} = \binom{5}{2} = \frac{5!}{2!3!} = 10\)
Each of the 3 children receives 1 pencil, totaling \(3 \times 1 = 3\) pencils. This leaves \(6 - 3 = 3\) pencils remaining.
Using the same formula for the remaining 3 pencils (\(n=3\)) among 3 children (\(r=3\)):
Number of ways to distribute remaining pencils: \(\binom{5}{2} = 10\)
There are 3 identical erasers (\(n=3\)) to be distributed among 3 children (\(r=3\)).
Number of ways to distribute erasers: \(\binom{5}{2} = 10\)
The total number of ways to distribute all items is the product of the ways for each item:
\(Total = 10 \, (\text{balloons}) \times 10 \, (\text{pencils}) \times 10 \, (\text{erasers})\)
\(Total = 1000\)
Therefore, there are 1000 distinct ways to distribute the items to the children according to the specified conditions.
If \(S=\{1,2,....,50\}\), two numbers \(\alpha\) and \(\beta\) are selected at random find the probability that product is divisible by 3 :
The probability of hitting the target by a trained sniper is three times the probability of not hitting the target on a stormy day due to high wind speed. The sniper fired two shots on the target on a stormy day when wind speed was very high. Find the probability that
(i) target is hit.
(ii) at least one shot misses the target. 