If k,m ,and n are positive real numbers such that k(m+n) = 152, m(n+k) =162 , and n(k+m) = 170, then kmn is  Choices
A) a) 672  B) b) 688  C) c) 704  D) d) 720  E) e) 750
km+kn = 152 --------------------------------------1)   mn+mk = 162---------------------------------------2)   kn+nm = 170---------------------------------------3)   Re-writing equation 3 as follows: kn+nm = 162 + 8 kn+nm= mn+mk + 8   kn = mk + 8 ............... (4)   Adding (1)(4)   2kn = 160   kn = 80   kmn has to be multiple of 80, only 720 fits in   Answer = d) 720
<result>D</result>
If k,m ,and n are positive real numbers such that k(m+n) = 152, m(n+k) =162 , and n(k+m) = 170, then kmn is