Question

[talanphuong]

trung binh cong cua 2 phan so bang 14/5,phan so thu 2 hon phan so thu1 la 7/4.tim phan so thu2

Answer 1

[Nguyễn Thị Quỳnh]

((a/b)+(c/d))/2=14/5

suy ra :a/b+c/d=(14/5):2=28/5

suy ra a/b=((28/5)-(7/4))/2=77/40

c/d=77/20+7/4=147/40

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