text: const CustomError = require("../extensions/custom-error");
  
  const MODERN_ACTIVITY= 15; 
  const HALF_LIFE_PERIOD= 5730;
  
  module.exports = function dateSample(sampleActivity) {
    if (arguments.length && (typeof sampleActivity === 'string') && (parseFloat(sampleActivity) > 0) && (parseFloat(sampleActivity) < MODERN_ACTIVITY)) {
      k = 0.693/HALF_LIFE_PERIOD;
      t = Math.log(MODERN_ACTIVITY/parseFloat(sampleActivity)) / k; 
  
      return Math.ceil(parseFloat(t));
    } else {
        return false;
    };
  };
  