Question

The average of 3 numbers is 19.

Two of the numbers are 17 and 24.
What is the third number?

Answer 1

Average of 15 numbers = 18

Average of 15 numbers = 18Sum of 15 numbers = 15×18 = 270

Average of 15 numbers = 18Sum of 15 numbers = 15×18 = 270Average of first 8 numbers =19

Average of 15 numbers = 18Sum of 15 numbers = 15×18 = 270Average of first 8 numbers =19Sum of first 8 numbers = 19×8 =152

Average of 15 numbers = 18Sum of 15 numbers = 15×18 = 270Average of first 8 numbers =19Sum of first 8 numbers = 19×8 =152Average of last 8 numbers =17

Average of 15 numbers = 18Sum of 15 numbers = 15×18 = 270Average of first 8 numbers =19Sum of first 8 numbers = 19×8 =152Average of last 8 numbers =17Sum of last 8 numbers =17×8 =136

Average of 15 numbers = 18Sum of 15 numbers = 15×18 = 270Average of first 8 numbers =19Sum of first 8 numbers = 19×8 =152Average of last 8 numbers =17Sum of last 8 numbers =17×8 =1368th number = Sum of first 8 +Sum of last 8 - total sum

Average of 15 numbers = 18Sum of 15 numbers = 15×18 = 270Average of first 8 numbers =19Sum of first 8 numbers = 19×8 =152Average of last 8 numbers =17Sum of last 8 numbers =17×8 =1368th number = Sum of first 8 +Sum of last 8 - total sum=152+136−270

Average of 15 numbers = 18Sum of 15 numbers = 15×18 = 270Average of first 8 numbers =19Sum of first 8 numbers = 19×8 =152Average of last 8 numbers =17Sum of last 8 numbers =17×8 =1368th number = Sum of first 8 +Sum of last 8 - total sum=152+136−270=18

Answer 2

16

Explanation:

Let the third number = x

Average = 19

`(17+24+x )/(3)=19\\41 + x = 19*3\\\\\\`

41 + x = 57

x = 57 - 41

x = 16