Bunuel wrote:
What is the average (arithmetic mean) of x, y and z?
(1) 3x – 2y + 7z = 23
(2) 4x – 3y + 5z = 5 and –x + 6y – 2z = 58
Kudos for a correct solution.
Solution: We need to find mean i.e \(\frac{x+y+z}{3}\).
In order to find this we need either values of x,y and z or value of x+y+z
Statement1 : We have 3 variables and 1 equation. So, we cannot find x,y and z. Finding x+y+z is also impossible here.
So, insufficient.
Statement2 : There is a small trap here. We have 3 variables and 2 equations,we cant find x,y and z individually. But adding those two equations we get the value of x+y+z. This is enough to find the mean.
So, sufficient.
Option B