设第一堆有x,则第二堆有:1300-x
(1-2/3)x=(1-5/7)(1300-x)
x/3=2(1300-x)/7
7x=6(1300-x)
7x=7800-6x
7x+6x=7800
13x=7800
x=600
1300-x=700