Rahul Kumar · 2026-07-01 · 3 helpful
But in question it is clearly mentioned that the exact no. Which is less or equal than 8 will be 20, so the remaining 10 has to be greater than 8. If we take rest 10 less than 8, so it will not satisfy the question needs
nav · 2026-07-01 · 2 helpful
i got stuck in the same question too :'0
so the logic is that we have fixed value of avg of 30 numbers = 8
so total sum of 30 numbers = 8x30 = 240
now we have a condition that strictly 20 numbers do not exceed 8, that means only the remaining 10 numbers can have values greater than or equal to 9, and the 20 numbers have to be 8 or less than 8,
so to maximize the avg of 20 numbers, we minimize the avg of remaining 10 numbers
the minimum value of those 10 numbers is 9
so their sum must be 9x10 = 90
now sum[total - 10 numbers] = 240 - 90 = 150
hence maximum sum of the 20 numbers can be 150
so their avg must be 150/20 = 7.5
a way of catching the error in our initial logic is that, since 8 is the overall avg of all 30 numbers, it cannot be the avg of the 20 numbers too unless the remaining 10 numbers are also equal to 8, but this is not possible because the question states that the remaining 10 numbers have to be greater than 8
hope this clears it up :)