SumDistinct in report builder 2

Revision 1
Dear,

I am building a report using report builder 2.
let say the data from my query is look like below:

Select membershipid,billamount,transactionAmount
From membership m inner join bill b on b.membershipid=m.id
left outer join transaction t on t.billId=b.id

MembershipId(membership Table) billAmount(bill) TransactionAmount (transaction)
1 100 20
1 100 20
1 100 50
1 100 10
2 50 10
2 50 10
2 50 20

when I used the row group in report builder on membershipId then add Total group
,report output is like this:
1 400 100
2 150 50

I want to see this output:
1 100 100
2 50 50


why this happen?and What should I do؟