how to get distinct records sql server

Question

If i have Two tables 

First

QuestionID(primary key)	Target value
1	100

 Second table

RecordID(primary key)	Achieved value	QuestionID (FORIGN KEY)
1	123	1
2	432	1

When i want to calculate the sum using Inner join i.e.

SELECT SUM(TargetValue) AS TARGET ,SUM(AchievedValue) AS ACHIEVED FROM First

INNER JOIN Second AS S ONS.QuestionID=First.QuestionID 

Where 1=1

 

Then it gives me SUM OF TARGET VALUE 200 Instead of 100 Why???