I need help with part B

Problem 2: A bumpy way For a given n, we make a structure of bumps by placing 2n rows of bumps as shown in the figure below for n = 2 (2n 4 and thus 4 rows) (a) (2 points) In terms of n, how many bumps are there in total? (your answer should be general for any n and in the simplest possible form you can make) When a ball is dropped as shown above, it moves either Left or Right upon hitting a bump. Let M be the set of paths that bring the ball on ts way down to the exact middle of the last row, which is possible since the last row has 2n bumps (an eve mbe (b) (2 points) Establish a one-to-one correspondence (bijection) between the set M and a special set of binary strings that you must clearly define