In a triangle ABC. if a + b - 3c = 0, then cos A + cos B is equal to:
1). 3(1 - cos C)
2). 3 cos C
3). 3 sin C
4). 3 cos (A - B)
If the probability density function of a continuous random variable X is defined by $f(x)=kx(2-x), 0
1). $\frac{3}{4}$
2). $\frac{1}{2}$
3). $\frac{3}{8}$
4). $\frac{1}{4}$
The co-ordinates of the point that divides the line joining the points P(2, 3, 1) and Q(5, 0, 4) in the ratio 1 : 2 are:
1). (3, 2, 2)
2). (3, 1,1)
3). (4, 1, 3)
4). $\frac{7}{3},1,\frac{5}{3}$
A bag contains 4 white, 5 red and 6 blue balls. Three balls are drawn at random from the bag. The probability that all
of them are red is:
1). $\frac{2}{91}$
2). $\frac{2}{77}$
3). $\frac{1}{22}$
4). $\frac{3}{22}$
If a, b and c are real numbers, then both the roots of the equation
( x — a )( x — b) + ( x — b)(x — c) + ( x — c )( x — a ) = 0
1). Are negative
2). Do not exist
3). Are positive
4). Are real