3 jam +90 menit - 1800 detik =...... menit

3 jam ×60 menit = 180 menit + 90 menit - 1800 dtk :60 = 30 mnit
=180 +90 -30
=270 -30
= 240 menit.

1 jam = 60 menit
1 jam = 3.600 detik
1 menit = 60 detik

Soal!
3 jam + 90 menit - 1.800 detik = … menit

Jawab!
= 3 jam + 90 menit - 1.800 detik
= ( 3 × 60 ) menit + 90 menit - ( 1.800 ÷ 60 ) menit
= 180 menit + 90 menit - 30 menit
= 270 menit - 30 menit
= 240 menit