Question

The average of 8 quantities is 12. The average of 5
of them is 9. What is the average of the remaining
three quantities?
​

Answer 1

Given:

• Average of 8 quantities→ 12
• Average of 5 of those quantities→ 9

________________________________

To Find:

The average of the remaining three quantities.

________________________________

Formula to be used:-

Average = Sum of n Numbers/n

_____________________________

Solution:

Average of 8 quantities→ 12

Sum of 8 Numbers = 12×8

= 96

Now,

Average of 5 of those quantities → 9

Sum of 5 Numbers= 9×5

=45

Hence,Sum of remaining Number be difference between them,

therefore–

Sum of Remaining (8-5) no.=96-45

==>51

Let found the Average of those 3 remain quantities.

Average = sum of n No./n

==>51/3

==>17

__________________________

Answer:-

17

Answer 2

Given:-

• The average of 8 quantities is 12

• The average of 5 of them is 9.

To Find:-

• The average of remaining Quantities.

Now,

As we know,

Average of all Quantities = Sum of Quantity/ No. Of quantity

So,

→ Sum of Quantity = Average of all Quantities × No. Of quantity

→ Sum of Quantity = 12 × 8

→ Sum of Quantity = 96.

Also Similarly,

→ Sum of Quantity = Average of all Quantities × No. Of quantity

→ Sum of Quantity = 5 × 9

→ Sum of Quantity = 45

Now,

→Sum of Rest Quantity= 96 - 45

→Sum of Rest Quantity = 51.

So,

→ Average of 3 Quantities = Sum of Quantity/ No. Of quantity

→ Average of 3 Quantities = 51/3

→ 17.

Hence, The Average of remaining three quantities is 17.