7/13乘6/29+6/13乘22/29
=6/13x/50+x/60=6.6
11x/300=6.6
x=6.6÷11/300
x=180乘7/29+6/13乘22/29
=6/13乘(7/29+22/29)
=6/13乘1
=6/13