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A boy added all natural numbers from 1 to 12, however he added one number twice due to which the sum becomes 80. What is the number which he added twice?
- a)3
- b)2
- c)7
- d)8
Correct answer is option 'B'. Can you explain this answer?
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Verified Answer
A boy added all natural numbers from 1 to 12, however he added one num...
Sum of all natural numbers from 1 to 12 = 78
By adding a number twice sum becomes 80
∴ the number which is added twice = 80 - 78 = 2
Most Upvoted Answer
A boy added all natural numbers from 1 to 12, however he added one num...
Sum of natural numbers:
The sum of natural numbers from 1 to n can be calculated using the formula:
Sum = (n/2) * (first term + last term)
Given information:
In this question, the boy added all natural numbers from 1 to 12, but he accidentally added one number twice, resulting in the sum becoming 80.
Steps to solve the problem:
To find the number that was added twice, we need to find the sum of the numbers from 1 to 12 without any duplications. Then we can subtract this sum from 80 to find the number that was added twice.
1. Find the sum of numbers from 1 to 12:
Using the formula, we can calculate the sum of natural numbers from 1 to 12 as follows:
Sum = (12/2) * (1 + 12) = 6 * 13 = 78
2. Subtract the sum without duplications from 80:
80 - 78 = 2
The number added twice is 2.
Therefore, option B is the correct answer.
The sum of natural numbers from 1 to n can be calculated using the formula:
Sum = (n/2) * (first term + last term)
Given information:
In this question, the boy added all natural numbers from 1 to 12, but he accidentally added one number twice, resulting in the sum becoming 80.
Steps to solve the problem:
To find the number that was added twice, we need to find the sum of the numbers from 1 to 12 without any duplications. Then we can subtract this sum from 80 to find the number that was added twice.
1. Find the sum of numbers from 1 to 12:
Using the formula, we can calculate the sum of natural numbers from 1 to 12 as follows:
Sum = (12/2) * (1 + 12) = 6 * 13 = 78
2. Subtract the sum without duplications from 80:
80 - 78 = 2
The number added twice is 2.
Therefore, option B is the correct answer.
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A boy added all natural numbers from 1 to 12, however he added one number twice due to which the sum becomes 80. What is the number which he added twice?a)3b)2c)7d)8Correct answer is option 'B'. Can you explain this answer?
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