The mass of packet rice and a packet of barley is 77.7 kg. The mass of 2 packets of rice and 3 packets of barley is 182.74 kg. Find the mass of 1 packet of rice?

pr = packet of rice
pb = packet of barley

1pr + 1pb = 77.7 2pr +3 pb = 182.74


1pr = 77.7 - 1pb
1pr = (182.74 - 3pb)/2


77.7 - 1pb = (182.74 - 3pb)/2
2(77.7 - 1 pb) = 182.74 - 3pb
155.4 - 2 pb = 182.74 - 3pb
155.4 = 182.74 - pb
-27.34 = -pb
pb = 27.34


1pr + 27.34 = 77.7
1 packet of rice = 50.36 kg