Question

The average of $x_1,x_2,x_3,x_4$ is 16. Half the sum of $x_2,x_3,x_4$ is 23. What is the value of $x_1$?

• A. $17$
• B. $18$
• C. $19$
• D. $20$

Answer 1

The correct option is B $18$

Given. the average of $x_1,x_2,x_3,x_4$ is $16$
$\therefore \frac{x_1+x_2+x_3+x_4}{4}=16$
$\therefore x_1+x_2+x_3+x_4=16\times 4=64$ ....(1)
Given, half the sum of $x_2,x_3,x_4$ is $23$
$\therefore \frac{x_2+x_3+x_4}{2}=23$
$\therefore x_2+x_3+x_4=46$ .....(2)
Subtracting equations (2) from (1), we get
$x_1=18$