Given a set {12, x ,17} , for what x would the mean be 14?

1 Answer
Dec 7, 2015

x=13

Explanation:

color(white)(xx)bar a =1/nsum_(i=1)^n a_i (the mean of a set of n data points)

color(white)(xx)14=1/3sum_(i=1)^3 a_i
=>(12+x+17)/3=14

Multiply both sides by 3
color(white)(xx)color(red)(3*)(12+x+17)/3=color(red)(3*)14
=>x+29=42

Add -29 to both sides
color(white)(xx)x+29color(red)(-29)=42color(red)(-29)
=>x=13