(1*3*5+2*6*10+7*21*35)/(1*2*5+2*4*10+7*14*35)
=(1*3*5+2*1*3*5+7*1*3*5)/(1*2*5+2*1*2*5+7*1*2*5)
=【1*3*5*(1+2+7)】/【1*2*5*(1+2+7)】
=1*3*5/(1*2*5
=3/2
=1.5
(1*3*5+2*6*10+7*21*35)/(1*2*5+2*4*10+7*14*35)
=(1*3*5+2*1*3*5+7*1*3*5)/(1*2*5+2*1*2*5+7*1*2*5)
=【1*3*5*(1+2+7)】/【1*2*5*(1+2+7)】
=1*3*5/(1*2*5
=3/2
=1.5