Question

The mean of 10 number is 55. If one number is excluded,their mean becomes 50. The excluded number is.......

Answer 1

Answer: 100

Step-by-step explanation: Mean of 10 numbers = 55

As 1 number is excluded,

So mean of 9 numbers = 50

Therefore, value of the excluded number = (10 x 55) - (9 x 50)

= 550 - 450

= 100

Answer 2

Answer:

The required number is 100

Step-by-step explanation:

Let the excluded number be x

So, 55 = sum of 10 numbers /10

550 = sum of 10 numbers(including x)

and

50 = sum of 9 numbers/9

450 = sum of 9 numbers(excluding x)

so we can say x = 550 - 450 [ sum of 10 numbers - sum of the rest 9 numbers]

x=100