A boy while playing with matchsticks observed that five matchsticks are required for making a single 'H' and ten matchsticks for two 'H' and so on. He tried obtaining the rule for calculating number of matchsticks required for making 'n' numbers of H. The correct rule is ______.
5n
Rule here is basically a mathematical relation between the number of matchsticks required and number of 'H' formed or made. Five matchsticks are required for making a single 'H'. Therefore, 10 matchsticks would be required for making two 'H' and hence 15 matchsticks would be required for making three 'H' and so on. So, the rule '5n' explains the relation.