goi so thoc o thua ruong thu nhat va thu hailan luot la a, b(a.b thuoc N*)
vi 2/3 so thoc o thua ruong thu nhat bang 4/5 so thoc o thua ruong thu 2
nen 2/3a=4/5b
a=4/5.b:2/3
a=4/5b.3/2
a=6/5b(1)
vi hai thua ruong thu hoach dc 990kg thoc
nen a+b=990(2)
thay (1) vao (2) ta dc
6/5b+b=990
6/5b+1.b=990
6/5b+5/5b=990
11/5b=990
b=990:11/5
b=990.5/11
b=450 thay vao (1) ta dc
a=6/5. 450
a=540
vay thua ruong thu nhat co 540kg thoc, thua ruong thu 2 co450kg thoc