# What is the error in the following question from gfg?

I tried to submit here the following code:

```def findMean(self, arr, queries, n, q):
# Complete the function
sum=0
count=0
li=[]
for i in range(0,q,2):
l=queries[i]
r=queries[i+1]
for j in range(l,r+1):
sum+=arr[j]
count+=1
mean=math.floor(sum/count)
li.append(mean)

return li
```

But I am getting some unexpected error, for instance for `2.72727272` the output needs to be `3` whereas for `4.6666` it needs to be `4`.

Can anyone help me find what math function I need or some other way I should use to solve such errors?

I modified your code but it will get TLE.

```import math
class Solution:
def findMean(self, arr, queries, n, q):
# Complete the function
# sum=0
# count=0
li=[]
for i in range(0,q,2):
l=queries[i]
r=queries[i+1]
s = 0
mean = 0
count = r - l + 1
for j in range(l,r+1):
s+=arr[j]
mean=(s//count)
li.append(mean)

return li
```

We can optimize and make it O(q + n) by calculating the prefix sum

You can undestand the concept for the prefix sum method from this link Mean Range Array