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The mean weight of a group of 10 items is 28 and that of another group of n items is 35.The mean of combined group of 10 + n items is found to be 30. The value of n is
- a)12
- b)10
- c)4
- d)2
Correct answer is option 'C'. Can you explain this answer?
Verified Answer
The mean weight of a group of 10 items is 28 and that of another group...
sum of weights of 10 items = 280
sum of weights of n items = 35n
so, sum of weights of (10 + n) items = 280 + 35n
so ,mean = (280 + 35 n) / (10 + n)
30(10 + n) = 280 + 35n
solving we get, n = 4
sum of weights of n items = 35n
so, sum of weights of (10 + n) items = 280 + 35n
so ,mean = (280 + 35 n) / (10 + n)
30(10 + n) = 280 + 35n
solving we get, n = 4
Most Upvoted Answer
The mean weight of a group of 10 items is 28 and that of another group...
Given:
- Mean weight of 10 items = 28
- Mean weight of n items = 35
- Mean weight of combined group of 10+n items = 30
To find: Value of n
Solution:
Let's start by using the formula for the mean of a group of items:
Mean = (Sum of all items) / (Number of items)
We can use this formula for each of the three groups mentioned in the question:
Group 1 (10 items):
Mean = 28
Number of items = 10
Sum of all items = 28 * 10 = 280
Group 2 (n items):
Mean = 35
Number of items = n
Sum of all items = 35n
Combined group (10+n items):
Mean = 30
Number of items = 10 + n
Sum of all items = 30 * (10 + n) = 300 + 30n
Now we can use the fact that the combined group consists of items from Group 1 and Group 2:
Sum of all items in combined group = Sum of all items in Group 1 + Sum of all items in Group 2
300 + 30n = 280 + 35n
Solving for n:
30n - 35n = 280 - 300
-5n = -20
n = 4
Therefore, the value of n is 4, which is option (c).
- Mean weight of 10 items = 28
- Mean weight of n items = 35
- Mean weight of combined group of 10+n items = 30
To find: Value of n
Solution:
Let's start by using the formula for the mean of a group of items:
Mean = (Sum of all items) / (Number of items)
We can use this formula for each of the three groups mentioned in the question:
Group 1 (10 items):
Mean = 28
Number of items = 10
Sum of all items = 28 * 10 = 280
Group 2 (n items):
Mean = 35
Number of items = n
Sum of all items = 35n
Combined group (10+n items):
Mean = 30
Number of items = 10 + n
Sum of all items = 30 * (10 + n) = 300 + 30n
Now we can use the fact that the combined group consists of items from Group 1 and Group 2:
Sum of all items in combined group = Sum of all items in Group 1 + Sum of all items in Group 2
300 + 30n = 280 + 35n
Solving for n:
30n - 35n = 280 - 300
-5n = -20
n = 4
Therefore, the value of n is 4, which is option (c).
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The mean weight of a group of 10 items is 28 and that of another group of n items is 35.The mean of combined group of 10 + n items is found to be 30. The value of n isa)12b)10c)4d)2Correct answer is option 'C'. Can you explain this answer?
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The mean weight of a group of 10 items is 28 and that of another group of n items is 35.The mean of combined group of 10 + n items is found to be 30. The value of n isa)12b)10c)4d)2Correct answer is option 'C'. Can you explain this answer? for JEE 2025 is part of JEE preparation. The Question and answers have been prepared according to the JEE exam syllabus. Information about The mean weight of a group of 10 items is 28 and that of another group of n items is 35.The mean of combined group of 10 + n items is found to be 30. The value of n isa)12b)10c)4d)2Correct answer is option 'C'. Can you explain this answer? covers all topics & solutions for JEE 2025 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for The mean weight of a group of 10 items is 28 and that of another group of n items is 35.The mean of combined group of 10 + n items is found to be 30. The value of n isa)12b)10c)4d)2Correct answer is option 'C'. Can you explain this answer?.
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