For part (a), what is the probability of this string, PPJJJ?

For part (b), what is the probability of each of these strings, PJJJ, PPJJJ, PJPJJ, PJJPJ? [Add these four.]

For part (c), what is the probability of each of these strings, PPJJJ, PJPJJ, PJJPJ, JPPJJ, JPJPJ, JJPPJ, JJPPP, JPJPP, JPPJP, PJJPP, PPJJP, PJPJP? [Add these 12.]