Question

The mean of 5 numbers is 20. If one number is excluded, mean of the remaining
numbers becomes 23. Find the excluded number.
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Answer 1

Mean of 5 numbers = 20 ______ [ GIVEN ]

Sum of 5 numbers = 20 × 5

= 100

So,.. we have total numbers = 100

If one is excluded. Means we have total 5 numbers, subtract one from it.

Now the left number is 4.

Mean of 4 numbers = 23 ____ [ GIVEN ]

Sum of 4 numbers = 23 × 4

= 92

______________________________

We have to find the excluded number.

i.e. Sum of 5 numbers - Sum of 4 numbers

→ 100 - 92

→ 8

______________________________

8 is the excluded number.

________ [ ANSWER ]

______________________________

Answer 2

ANSWER...................,

The mean of 5 number = 20

The sum of 5 number = 5 × 20 = 100

If one number is excluded ,

Then mean of 4 number = 23

Sum of 4 number = 4 × 23 = 92

∴excluded number = 100 - 92 = 8