Question

The average age of three persons is 18. If two of them are included then the average age becomes 20. If the age of 1st is 17 then find the age of the remaining persons

Answer 1

Let x,y and z be three no.
x=17
so
$\frac{x + y }{2} = 20$
17+y=20 ×2
17+y=40
y=23
$\frac{x + y + z}{3} = 18$
$\frac{17 + 23 + z}{3} = 18$
40+z=54
z=54-40
z=14
so x=17
y=23
z=14