ada yg bisa jelasin cara ngerjainnya nomor 85 sama 86??

85. 2 ha = 20.000 m2
pupuk = 40 kg
urea 30% = 30/100 . 40 kg = 12 kg

kadar N dalam urea [CO(NH2)2]
= 2. Ar N/Mr x 100%
= 2.14/60 x 100%
= 46,67%

massa N tiap 20.000 m2 = 46,67% . 12 kg
= 5600 gram

massa N tiap 1 m2 = 5600 gram/20.000 m2
=0,28 gram/m2