jawab nomor 20-21 beserta caranya dengan jelas dan lengkap

20) selisih
= 13.970 - 13.750
= 220 ( D )

21) misal berat badan 3 siswa = a
44,0 = ( 32 × 42,5 ) + ( 3 × a ) / ( 32 + 3 )
44,0 = 1.360 + 3a / 35
44,0 × 35 = 1.360 + 3a
1.540 = 1.360 + 3a
3a = 1.540 - 1.360
3a = 180
a = 60 kg ( C )