GMAT Practice Question: The average (arithmetic mean) of the positive integers x, y, and z is 3 . If x<y<z...
Question
The average (arithmetic mean) of the positive integers x, y, and z is 3 . If x<y<z, what is the greatest possible value of z ?
- 5
- 6
- 7
- 8
- 9
Topics: word problems, inequalities, mean
Solution
Step 1
We translate the statement about the average into an equation.
\frac{x+y+z}{3} = 3
Step 2
We solve this equation to find the sum of the three integers.
x + y + z = 9
Step 3
We need to maximize z given x<y<z and that x,y,z are positive integers, so we choose the smallest possible values for x and y.
x = 1; y = 2
Step 4
We substitute x and y into the sum to find z.
z = 9 - 1 - 2 = 6
Answer
6
