interface Reading {
  sensor: string;
  value: number;
}

const readings: Reading[] = [
  { sensor: 'A', value: 12.4 },
  { sensor: 'B', value: 15.1 },
  { sensor: 'A', value: 13.2 },
];

const total = readings.reduce((sum, reading) => sum + reading.value, 0);
const average = total / readings.length;

console.log(`Average: ${average.toFixed(2)}`);