Question

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

Answer 1

To find the seventh result, we can use the given averages and the total average.

1. The average of 13 results is 70, so the sum of all 13 results is 13 * 70 = 910.

2. The average of the first seven results is 65, so the sum of the first seven results is 7 * 65 = 455.

3. The average of the last seven results is 75, so the sum of the last seven results is 7 * 75 = 525.

Now, we can find the seventh result:

- Total sum of all 13 results = 910.
- Total sum of the first seven results = 455.
- Total sum of the last seven results = 525.

To find the seventh result, we subtract the total sum of the first seven results from the total sum of all 13 results and then add the total sum of the last seven results:

Seventh result = (Total sum of all 13 results - Total sum of the first seven results) + Total sum of the last seven results
Seventh result = (910 - 455) + 525
Seventh result = 455 + 525
Seventh result = 980

So, the seventh result is 980.