Solution :
It is given that four different prizes were awarded. So,
a). 4 ways for person 47 to win a prize
99 ways to give out the 2nd prize
98 ways to give the 3rd prize
97 ways to give the last prize
∴ P(99,3) = 99 x 98 x 97
b). 1 way to give person 47 their prize
1 way to give person 19 their prize
98 ways to give out the 3rd prize
97 ways to give out the last prize
So, P(98,2) = 98 x 97