c. Empat anggota
Jawaban : Y = {7, 11, 13, 17, 19, 23}
a) Dua anggota
{7, 11}, {7,13}, {7,17}, {7, 19}, {7,23}, {11,13}, {11, 17}, {11, 19}, {11, 23}, {13, 17}, {13, 19}, {13, 23}, {17, 19}, {17, 23}, {19, 23}
b) Tiga anggota
{7, 11, 13}, {7, 11, 17}, {7, 11, 19}, {7, 11, 23}, {7, 13, 17}, {7,13, 19}, {7, 13, 23}, {7, 17, 19}, {7, 17, 23}, {7, 19, 23}, {11, 13, 17}, {11, 13, 19}, {11, 13, 23}, {11, 17, 19,}, {11, 17, 23}, {11, 19, 23}, {13, 17, 19}, {13, 17, 23}, {13, 19, 23}, {17, 19, 23}
c) Empat anggota
{7, 11, 13, 17}, {7, 11, 13, 19,}, {7, 11, 13, 23}, {7, 11, 17, 19}, {7, 11, 17, 23}, {7, 11, 19, 23}, {7, 17, 19, 23}, {7, 13, 17, 19}, {7, 13, 17, 23}, {7, 17, 19, 23}, {11, 13, 17, 19}, {11, 13, 17, 23}, {11, 13, 19, 23}, {11, 17, 19, 23}, {13, 17, 19, 23}
Demikian kunci jawaban Matematika kelas 7 halaman 144, lima soal dalam Ayo Kita Berlatih 2.5.***