Twenty students compete in a school-wide marathon and each student is of comparable running ability. Of the 20 students, 15 were boys and 5 were girls. What is the probability that boys will place 1st, 2nd, and 3rd in the marathon?

0.3991

Step-by-step explanation:

Number of Boys=15

Number of Girls =5

Total=15+5=20

Note that as each boy wins, the number of male contestants reduces. Thus is a probability of selecting an item without replacement.

P(1st boy winning) = 15/20

P(2nd boy winning) =14/19

P(3rd boy winning)=13/18

Therefore:

P(boys will place 1st, 2nd, and 3rd in the marathon)

= 15 /20 X 14/19 X 13/18

=91/228

=0.3991