[tex]\text{Hello there!}\\\\\text{Turn the statements into equations:}\\\\\text{Graham:}\\\\y=-50x+14,040\\\\\text{Max:}\\\\y=20x+12,500\\\\\text{We need to find when they will meet at the same altitude, so solve both}\\\text{of the equations together}\\\\-50x+14,040=20x+12,500\\\\\text{Subtract 20x from both sides}\\\\-70x+14,040=12,500\\\\\text{Subtract 14,040 from both sides}\\\\-70x=-1,540\\\\\text{Divide both sides by -70}\\\\x=22\\\\\boxed{\text{Answer: 22 minutes}}[/tex]
