Giải:
a, `p_X + e_X + n_X = 82`
`-> 2p_X + n_X = 82` (1)
`2p_X - n_X = 34` (2)
(1), (2) `-> p_X = e_X = 29`; `n_X = 24`
b, `p_X = 13/15n_X` (3)
(1), (3) `-> 2 . 13/15n_X + n_X = 82`
`-> 41/15n_X = 82`
`-> n_X = 30`
`-> p_X = e_X = 13/15 . 30 = 26`
c, `p_Y + e_Y + n_Y = p_X = 26`
`-> 2p_Y + n_Y = 26`
`-> n_Y = 26 - 2p_Y`
Mặt khác, `p_Y <= n_Y <= 1,5p_Y`
`-> p_Y <= 26 - 2p_Y <= 1,5p_Y`
`-> 3p_Y <= 26 <= 3,5p_Y`
`-> 7,42 <= p_Y <= 8,67`
`-> p_Y = e_Y = 8`
`-> n_Y = 26 - 2 . 8 = 10`