# The average of 13 results is 70. The average of first seven is 65 :

The average of 13 results is 70. The average of first seven is 65 and that of the last seven is 75, the seventh result is:

- 67
- 68
- 70
- 70.5

**Answer: (3) 70 **

**Explanation:-**

The average of 13 results = 70

Then, the sum of 13 results = 70 x 13

= 910

The average of first seven results = 65

Then, the sum of first seven results = 65 x 7

= 455

The average of last seven results = 75 x 7

= 525

So, The seventh result = (455 + 525) – 910

= 980 – 910

= 70

Then, the seventh result is 70.

Hence, the answer is (3) 70.