Re: maths

Posted by s on Apr 21, 2012; 7:18pm
URL: http://discussion-forum.276.s1.nabble.com/maths-tp7475141p7487772.html


1.Given x  y  z, and x + y + z = 9, the maximum value of x + 3y +
5z is
(A) 27,
(B) 42,
(C) 21,
(D) 18.

2.If a2 + b2 + c2 = 1, then ab + bc + ca is,
(A) -0.75,
(B) Belongs to the interval [-1, -0.5],
(C) Belongs to the interval [0.5, 1],
(D) None of the above.

3.What is the maximum value of a(1 - a)b(1 - b)c(1 - c), where a, b, c
vary over all positive fractional values?
A. 1
B . 1/8
C. 1/27
D. 1/64