text: const MODERN_ACTIVITY= 15; 
  const HALF_LIFE_PERIOD= 5730;
  
  module.exports = function dateSample(sampleActivity) {
    if (typeof sampleActivity !== 'string'  ) return false;
  
    sampleActivity = parseFloat(sampleActivity);
    if (typeof sampleActivity !== 'number' || Number.isNaN(sampleActivity) ) return false;
  
    let k = 0.693 / HALF_LIFE_PERIOD;
    let t = Math.ceil(Math.log(MODERN_ACTIVITY/ Number(sampleActivity))/k);
    
    return t> 0 && t < 50000 ? t : false;
  };
  