JEE Main 2021 Mathematics question

Let other two numbers be a, (21 – a). The mean of 6 distinct observations is 6.5 and their variance is 10.25. If 4 of the 6 observations are 2, 4, 5 and 7, then the remaining two observations are :

• (A)10, 11Correct
• (B)3, 18
• (C)8, 13
• (D)1, 20