fatt52

Verified answer

vcp=(s1+s2+s3/(t1+t2+t3)

t1=s1/v1    t2=s2/v2    t3=s3/v3

s1=s2=s3=s/3

vcp=3*v1*v2*v3/(v1*v2+v2*v3+v1*v3)

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