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From numbers 1 to 15 two no are selecte...

From numbers 1 to 15 two no are selected what is the probability that both the selected no . Are even numbers.

A

`0.20`

B

`0.30`

C

`0.25`

D

`0.35`

Text Solution

AI Generated Solution

The correct Answer is:
To solve the problem of finding the probability that both selected numbers from 1 to 15 are even numbers, we can follow these steps: ### Step 1: Identify the Total Numbers The total numbers from 1 to 15 are: \[ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 \] Thus, the total count of numbers is: \[ \text{Total Numbers} = 15 \] **Hint:** Count all the integers from 1 to 15 to find the total. ### Step 2: Identify the Even Numbers The even numbers between 1 and 15 are: \[ 2, 4, 6, 8, 10, 12, 14 \] Thus, the total count of even numbers is: \[ \text{Total Even Numbers} = 7 \] **Hint:** List out the even numbers in the given range to find how many there are. ### Step 3: Calculate the Total Ways to Select 2 Numbers The total ways to select 2 numbers from 15 can be calculated using the combination formula: \[ \binom{n}{r} = \frac{n!}{r!(n-r)!} \] Where \( n \) is the total number of items to choose from, and \( r \) is the number of items to choose. For our case: \[ n = 15, \quad r = 2 \] So, \[ \text{Total Ways to Select 2 Numbers} = \binom{15}{2} = \frac{15!}{2!(15-2)!} = \frac{15 \times 14}{2 \times 1} = 105 \] **Hint:** Use the combination formula to find the number of ways to choose 2 items from a larger set. ### Step 4: Calculate the Ways to Select 2 Even Numbers Now, we calculate the ways to select 2 even numbers from the 7 even numbers: \[ \text{Ways to Select 2 Even Numbers} = \binom{7}{2} = \frac{7!}{2!(7-2)!} = \frac{7 \times 6}{2 \times 1} = 21 \] **Hint:** Again, use the combination formula to find the number of ways to choose 2 even numbers. ### Step 5: Calculate the Probability The probability \( P \) that both selected numbers are even is given by the ratio of the number of favorable outcomes to the total outcomes: \[ P(\text{both even}) = \frac{\text{Ways to Select 2 Even Numbers}}{\text{Total Ways to Select 2 Numbers}} = \frac{21}{105} \] Simplifying this fraction: \[ P(\text{both even}) = \frac{1}{5} \] **Hint:** The probability is found by dividing the number of successful outcomes by the total outcomes. ### Final Answer Thus, the probability that both selected numbers are even is: \[ \boxed{\frac{1}{5}} \]
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