The total of three integers' squares is 138, whereas the sum of their products divided by two is 131. Their total is:
A. 20
B. 30
C. 40
D. None of these
Answer:A
The total of three integers' squares is 138, whereas the sum of their products divided by two is 131. Their total is:
A. 20 B. 30 C. 40 D. None of these
Explanation: Let's call the numbers a, b, and c.Then (ab + bc + ca) = 131 and a2 + b2 + c2 = 138.2(ab + bc + ca) = 138 + 2 x 131 = 400. (a + b + c)2 = a2 + b2 + c2 + 2(ab + bc + ca) = 138 + 2 x 131 = 400.The sum of (a + b + c) is 400, which equals 20.