Pretend there was a plan 6 that the king of Montarek wanted to present to the peasant. This time, he
starts with 12 rubas on the first square, and he doubles that to 24 rubas on the second square. The third
square has 48 rubas, and the pattern continues to double up to 20 squares.
a. How many rubas will be on the 20th square?
b. Write an equation to represent plan 6.