Could it be 12? Difference between 16-13=3, 13-7=6. 4-3=1, 3-1=2. Seems as if for each column, difference between first and second row is one half the difference between the 2nd and third rows
Joe: 8 songs in 10 minutes = 8/10 = 0.8 songs per minute
Jasmine: 12 songs in 15 minutes = 12/15 = 0.8 songs per minute
they are downloading at the same speed
binomial(16 + 7, 16) 2^(-(16 + 7)) = ((16 + 7)!)/(16! 7! 2^(16 + 7)) = 245157/8388608 ≈ 0.02922 ≈ 1/34.22
(assuming children are independent and male and female are equally likely)
| probability
less than 16 boys | 0.9534
16 or less boys | 0.9827
more than 16 boys | 0.01734
16 or more boys | 0.04657
fraction of boys | 16/(16 + 7) ≈ 0.695652
fraction of girls | 7/(16 + 7) ≈ 0.304348
expected value | 11.5
standard deviation | 2.398
variance | 5.75
11.5