Question

Average of 5 numbers is 20 . If three numbers are 18 ,20, 16 . Find the average of rest two numbers . Answer fast . ​

Answer 1

Answer:

Average of 15 numbers = 18

Sum of 15 numbers = 15×18 = 270

Average of first 8 numbers =19

Sum of first 8 numbers = 19×8 =152

Average of last 8 numbers =17

Sum of last 8 numbers =17×8 =136

8th number = Sum of first 8 +Sum of last 8 - total sum

=152+136−270

=18

Answer 2

Given:

Average of 5 numbers = - 20

Sum of three numbers = 32

Formula:

Average = Sum of numbers/Total numbers

Calculation:

Let the sum of the two numbers be ‘x’

According to the question,

32 + x = - 20 × 5

⇒ 32 + x = - 100

⇒ x = - 132

∴ Required average = - 132/2 = - 66