Question

There are five puppies in a litter. If the probability that a puppy is male is 0.5, what is the probability that at most one puppy in the litter is male?

a. 0.1563

b. 0.1875

c. 0.5

d. 0.8125

Answer 1

Probability that none are male=(½)⁵=1/32. (The probability of female is also ½.)

Probability that just one is male is found by considering all the possible arrangements of puppies in the litter in which only one is male: MFFFF, FMFFF, FFMFF, FFFMF, FFFFM (5 positions of 1 male in the litter).

So the probability of just one male=5(½)⁵=5/32.

Add that to the probability of no males=6/32=3/16=0.1875 (answer option b).