Solve the following linear programming problem graphically:
Maximize : `z=60x+15y`
Subject to : `x+yle50`
`3x+yle90`
`xge0`
`yge0`

Explanation

To solve the linear programming problem graphically, we will follow these steps:

### Step 1: Define the Objective Function and Constraints
We need to maximize the objective function:
\[ z = 60x + 15y \]
Subject to the constraints:
1. \( x + y \leq 50 \)
2. \( 3x + y \leq 90 \)
3. \( x \geq 0 \)
4. \( y \geq 0 \)