540 detik + 0,5 jam=...... menit

540 detik + 0,5 jam = (540 : 60) menit + (0,5 x 60) menit
                                = 9 menit + 30 menit
                                = 39 menit

540 detik = 540/60 menit= 9 menit
0,5 jam = 0,5 *60 menit = 30 menit
-----—---------------------------------------------- +
= 39menit