I toss a coin which lands heads with probability p let wh

Question

Question: I toss a coin which lands heads with probability p. Let W_H be number of tosses till I get a head, W_HH the number of tosses till I get two heads in a row, and W_HHH the number of tosses till I get three heads in a row. Find:

a) E(W_H): 

b) E(W_HH) [Hint: condition on whether the first toss was heads or tails]:

c) E(W_HHH) [Hint: condition on W_T].

d) Generalize to find the expected number of tosses to obtain n_t heads in a row