Find the number of matchsticks required for making 'n' 3s.
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 ______.
Observe the pattern : Find the number of matchsticks required to make 'n' number of 2’s.
If each matchbox contains 50 matchsticks, the number of matchsticks required to fill n such boxes is