Question

The average of 7 number is 52.if 5 new numbers with sum of deviation 17 from average are included and 3 numbers 56,57,51 are excluded, then find the new average?

Answer 1

Answer:

Step 1:

Average of 7 numbers = 52

∴ Sum of deviation of 7 numbers = 52 * 7 = 364

Step 2:

Now,  

The sum of deviations of 5 new members = 17

So, the new number after adding 5 numbers will be = 7 + 5 = 12

∴ Sum of deviation of 12 numbers = 364 + 17 = 381

Step 3:

3 of the numbers 56, 57 & 51 are excluded

So, the new number after excluding 3 numbers will be = 12 – 3 = 9

∴ Sum of deviation of 9 numbers = 381 – (56+57+51) = 381 – 164 = 217

Step  4:

Thus,  

The new average of 9 numbers will be

= 217 / 9

= 24.11