设甲班有X人,乙班有y人
x*(1-2/15)*3/4=(y+2X/15)*3/5
13x/15*3/4=(y+2x/15)*3/5
13x/60=y/5+6x/75
13x*5=60y+6x*4
65x=60y+24x
41x=60y
x/y=60/41
设甲班有X人,乙班有y人
x*(1-2/15)*3/4=(y+2X/15)*3/5
13x/15*3/4=(y+2x/15)*3/5
13x/60=y/5+6x/75
13x*5=60y+6x*4
65x=60y+24x
41x=60y
x/y=60/41