The sum of the squares of three numbers is 41, while the sum of their products taken two at a time is 20. Their sum is:	Select:
A) 10 B) 5 C) 9 D) 15 E) None of these
x^+y^2+z^2=138   xy+yz+zx=131   as we know.. (x+y+z)^2=x^2+y^2+z^2+2(xy+yz+zx)   so (x+y+z)^2=41+(2*20)   (x+y+z)^2=81   so x+y+z=9   ANSWER:9
<result>C</result>
The sum of the squares of three numbers is 41, while the sum of their products taken two at a time is 20. Their sum is: