7. The sum of the squares of three numbers is 138, while the sum of their products taken two at a time is 131. Their sum is:
A. 30
B. 40
C. 20
D. 60
7. The sum of the squares of three numbers is 138, while the sum of their products taken two at a time is 131. Their sum is:
A. 30
B. 40
C. 20
D. 60